プロフィール詳細

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Anatoli K.に依頼

Australia

Senior Scientific Editor & Physics Consultant | AMO, Attosecond & Computational Physics | Scientific Publishing

プロフィール概要

Emeritus Professor of Physics at the Australian National University with extensive experience in atomic, molecular and optical physics, photoionization, attosecond science and computational physics. I have published more than 270 peer-reviewed research articles, with an h-index of 47, and have extensive experience preparing manuscripts for leading international physics journals and responding to peer review. I offer substantive scientific editing and consulting rather than simple proofreading. I can critically assess a manuscript's scientific argument, structure, presentation of results and readiness for peer review; improve technical English and clarity; advise on journal selection and publication strategy; and help authors prepare effective responses to referees. My particular expertise includes atomic and molecular physics, quantum physics, photoionization, ultrafast and attosecond science, laser-matter interactions and computational physics. I am especially interested in helping researchers whose science is strong but whose manuscript would benefit from an experienced independent assessment before submission or revision. I also provide scientific and language editing of theses and thesis chapters. For assessed student work, my role is strictly editorial and advisory: I do not produce original work for submission as another person's own.

専門分野

• ★ Computational Physics
• ☆ Quantum Mechanics
• ☆ Theoretical Physics

サービス

• Writing
• Research
• Consulting
• Data & AI

Writing Technical Writing, General Proofreading & Editing, Translation

Research Gap Analysis, Scientific and Technical Research, Systematic Literature Review

Consulting Scientific and Technical Consulting

Data & AI Data Visualization, Data Processing, Data Insights

職務経験

Emeritus Professor

Australian National University

1月 2026 - 現在

Professor

Australian National University

1月 2006 - 現在

Senior Fellow

Australian National University

1月 2001 - 1月 2006

Senior Research Fellowship

The Australian National University

1月 1997 - 1月 2001

Research Fellow

Flinders University of South Australia

1月 1991 - 1月 1997

学歴

PhD (Theoretical Physics)

Fiziko-tekhnicheskij institut imeni A F Ioffe RAN

- 4月 1986

BSc (Physics of Semiconductors)

Saint Petersburg State Polytechnical University

9月 1971 - 2月 1977

認定資格

• Fellow of the American Physical Society

  The American Physical Society

  1月 2026 - 現在

出版物

JOURNAL ARTICLE

Circularly polarized RABBITT on atomic shells with large orbital momentum @article{cdedad27da4543b894465ea00c018c08, title = "Circularly polarized RABBITT on atomic shells with large orbital momentum", abstract = "In light atoms, the technique of Reconstruction of Attosecond Bursts by Interference of Two-Photon Transitions (RABBITT), driven by circularly polarized radiation, enables a complete retrieval of ionization amplitudes in the XUV+IR regime, including their relative phases (Kheifets 2024 Phys. Rev. Res. 6 L012002). In this work, we extend this method to heavier atoms by conducting numerical simulations of circularly polarized RABBITT on the Kr 3d and Xe 4d atomic shells. The XUV ionization dynamics in these atoms differ markedly due to the presence of a {\textquoteleft}giant{\textquoteright} shape resonance in the 4 d → E f ionization channel of Xe, a feature absent in Kr. Nevertheless, when an IR photon is added to the XUV ionization, the results for Kr and Xe are surprisingly similar, with the ratio of absorption/emission matrix elements and their relative phases remaining close in value. Moreover, these ratios and phases show minimal variation even when the Xe atom is encapsulated within a C60 fullerene cage. In search for the Cooper-like minimum in the IR absorption amplitude ratios predicted in Ji et al (2024 J. Phys. B 57 235601), we extend our investigation to the Ce 4f shell where this minimum is indeed present.", keywords = "atomic ionization, Attosecond science, RABBITT, ultrafast science", author = "Kheifets, \{Anatoli S.\}", note = "{\textcopyright} 2025 The Author(s). Published by IOP Publishing Ltd.", year = "2025", month = feb, day = "28", doi = "10.1088/1361-6455/ada98b", language = "English", volume = "58", pages = "1--10", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "4", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Direct double ionization of the He-like B3+ ion by a single photon @article{6e3da390685241faa09ced66f6395a06, title = "Direct double ionization of the He-like B3+ ion by a single photon", abstract = "Within a joint experimental and theoretical research project, double photoionization of the He-like B3+ ion by a single photon was studied in the energy range from approximately 350 to 1160 eV. With the parent-ion beam in the experiment containing both 1s21S ground-state (90.9\%) and 1s2sS3 metastable B3+ ions (9.1\%), two contributions to the apparent single- and double-ionization cross sections, σ34app and σ35app, respectively, are involved in the measurements. Ratios Y(5+)/Y(4+) of double- over single-ionization yields were experimentally determined. By multiplying the measured ratios by the known cross section σ34app, the apparent cross section σ35app for double ionization was inferred. Using the information thus obtained, the measured yield of B5+ ions produced from hydrogenlike B4+ could also be normalized. The results show good agreement with theoretical benchmark cross sections σ45 for single photoionization of B4+. Convergent close-coupling calculations were performed to determine double-photoionization cross sections σ35 for B3+(1s2) and B3+(1s2s) ions. The result for the ground state agrees very well with theoretical data obtained previously with an intermediate-energy R-matrix approach. Within the systematic uncertainty of the normalized experimental cross sections, calculated and measured data are in agreement with one another.", author = "A. M{\"u}ller and Hillenbrand, \{P. M.\} and Wang, \{S. X.\} and S. Schippers and I. Bray and Kheifets, \{A. S.\} and E. Lindroth and S. Reinwardt and M. Martins and J. Seltmann and F. Trinter", note = "{\textcopyright} 2025 authors. Published by the American Physical Society.", year = "2025", month = feb, doi = "10.1103/PhysRevA.111.023115", language = "English", volume = "111", pages = "1--9", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "2", } . Physical Review A.

Singor, Adam J. C., Fursa, Dmitry, V, Bray, Igor, Kheifets, Anatoli S. (2025). Attosecond time delays at Cooper minima in valence-shell photoionization of alkali-metal and alkaline-earth-metal atoms . Physical Review A.

(2025). Circularly polarized RABBITT on atomic shells with large orbital momentum .

Ivanov, I. A., Kheifets, A. S., Landsman, A. S. (2025). Relativistic spin-flip effect in the attoclock . Physical Review A.

Mueller, A., Hillenbrand, P. -m., Wang, S. -x., Schippers, S., Reinwardt, S., Martins, M., Seltmann, J., Trinter, F., Bray, I., V. Fursa, D., et al. (2025). Single and double photoionization of the Li-like B2+ion: Strong ionization-excitation contributions . Physical Review A.

Double- K -hole resonances in single photoionization of He-like B3+ ions @article{112565fc9ae54838a4f15a5c7fbc6124, title = "Double- K -hole resonances in single photoionization of He-like B3+ ions", abstract = "Within a joint experimental and theoretical research project, single photoionization of He-like B3+ ions was investigated in the energy range from approximately 250 to 1200 eV. With the parent-ion beam in the experiment containing both 1s2S1 ground-state and 1s2sS3 metastable B3+ ions, double-core-hole resonances could be studied. Two series of hollow resonant states were observed, one populated by K-shell double excitation 1s2S1→2 ′P1 (a=s,p; ′=p,s; n=2,3,,6) at photon energies up to about 510 eV, the other by K-shell single excitation 1s2sS3→2′P3 (a=s,p; ′=p,s; n=2,3, ,6) at energies up to about 310 eV. High resolving powers up to approximately 29000 were achieved. The relativistic many-body perturbation theory was employed to determine level-to-level cross sections for K-shell excitation with subsequent autoionization. The resonance energies were calculated with inclusion of electron correlation and radiative contributions. The energy uncertainties of the most prominent resonances are estimated to be below ±1meV. Convergent close-coupling (CCC) calculations provided single-photoionization cross sections σ34 for B3+ including the resonant and nonresonant channels. Apart from the resonances, σ34 is dominated by direct ionization in the investigated energy range. The contribution σ34dir of the latter process to σ34 was separately determined by using the random-phase approximation with exchange and relativistic Hartree-Fock calculations which agree very well with previous calculations. Direct ionization of one electron accompanied by excitation of the remaining electron was treated by the CCC theory and found to be a minor contribution to σ34.", author = "A. M{\"u}ller and Hillenbrand, \{P. M.\} and Wang, \{S. X.\} and S. Schippers and E. Lindroth and F. Trinter and J. Seltmann and S. Reinwardt and M. Martins and Kheifets, \{A. S.\} and I. Bray", note = "Publisher Copyright: {\textcopyright} 2024 American Physical Society. ", year = "2024", month = dec, doi = "10.1103/PhysRevA.110.062802", language = "English", volume = "110", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Fano-line-shape metamorphosis in resonant two-photon ionization @article{e0508fe97a564eefa4346c9a3a3b825f, title = "Fano-line-shape metamorphosis in resonant two-photon ionization", abstract = "In the Fano resonant ionization process, a decaying autoionizing state (AIS) is imbedded in the continuum resulting in a characteristic asymmetric photoelectron line shape. When the ionizing XUV pump is aided by a weak IR probe, the resonant path of the Fano process is transferred to the adjacent sidebands. As the XUV-IR delay grows, this resonant part of the sideband becomes decoupled from the embedding continuum. In result, the sideband line shape becomes symmetric and its magnitude decreases exponentially with the timing constant of the AIS decay. In the present work we simulate this process to extract the lifetime of several AISs in the He atom and the Li+ ion with sufficient numerical accuracy. The proposed method can be realized experimentally in diverse quantum systems ranging from nuclei to nanofabricated solids.", author = "Serov, \{Vladislav V.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2024 American Physical Society.", year = "2024", month = oct, doi = "10.1103/PhysRevA.110.043107", language = "English", volume = "110", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Relation between photoionisation cross sections and attosecond time delays @article{a647b9d901d34e799b4bccc82dcbdea0, title = "Relation between photoionisation cross sections and attosecond time delays", abstract = "Determination and interpretation of Wigner-like photoionisation delays is one of the most active fields of attosecond science. Previous results have suggested that large photoionisation delays are associated with structured continua, but a quantitative relation between photoionisation cross sections and time delays has been missing. Here, we derive a Kramers-Kronig-like relation between these quantities and demonstrate its validity for (anti)resonances. This new concept defines a topological analysis, which rationalises the sign of photoionisation delays and thereby sheds new light on a long-standing controversy regarding the sign of the photoionisation delay near the Ar 3s Cooper minimum. Our work bridges traditional photoionisation spectroscopy with attosecond chronoscopy and offers new methods for analysing and interpreting photoionisation delays.", keywords = "attosecond, Cooper minimum, cross sections, Fano resonance, photoionisation delays", author = "Ji, \{Jia Bao\} and Kheifets, \{Anatoli S.\} and Meng Han and Kiyoshi Ueda and \{Jakob W{\"o}rner\}, Hans", note = "Publisher Copyright: {\textcopyright} 2024 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.", year = "2024", month = sep, day = "1", doi = "10.1088/1367-2630/ad7633", language = "English", volume = "26", journal = "New Journal of Physics", issn = "1367-2630", publisher = "Institute of Physics", number = "9", } . New Journal of Physics.

First-principles simulations of high-order harmonics generation in thin films of wide bandgap materials [Invited] @article{d3dd303c8ecc4e5c82508a5e637670a0, title = "First-principles simulations of high-order harmonics generation in thin films of wide bandgap materials [Invited]", abstract = "High-order harmonics generation (HHG) is the only process that enables tabletop-sized sources of extreme ultraviolet (XUV) light. The HHG process typically involves light interactions with gases or plasma––material phases that hinder wider adoption of such sources. This motivates the research in HHG from nanostructured solids. Here, we employ the time-dependent density function theory (TDDFT) to investigate material platforms for HHG at the nanoscale using first-principles supercomputer simulations. We reveal that wide bandgap semiconductors, aluminum nitride (AlN) and silicon nitride (Si3N4), are highly promising for XUV light generation when compared to silicon, one of the most common nonlinear nanophotonic materials. In our calculations, we assume excitation with a 100 fs pulse duration, 1 × 1013 W/cm2 peak power, and 800 nm central wavelength. We demonstrate that in AlN material the interplay between the crystal symmetry and the incident light direction and polarization can enable the generation of both even and odd harmonics. Our results should advance the development of high-harmonics generation of XUV light from nanostructured solids.", author = "Albert Mathew and Sergey Kruk and Shunsuke Yamada and Kazuhiro Yabana and Anatoli Kheifets", note = "Publisher Copyright: {\textcopyright} 2024 Optica Publishing Group.", year = "2024", month = aug, doi = "10.1364/JOSAB.512444", language = "English", volume = "41", pages = "1665--1670", journal = "Journal of the Optical Society of America B: Optical Physics", issn = "0740-3224", publisher = "Optica Publishing Group", number = "8", } . Journal of the Optical Society of America B: Optical Physics.

Evidence for nonzero electron velocity at the tunnel exit in strong-field atomic ionization @article{0ed41a5a18a045959eab57c54664191c, title = "Evidence for nonzero electron velocity at the tunnel exit in strong-field atomic ionization", abstract = "We provide some evidence for nonzero electron velocity at the tunnel exit in strong-field atomic ionization. Our investigation is based on the analysis of a suitably chosen correlation function which describes correlations between the two observables: the longitudinal electron velocity and the appearance of the photoelectron in the continuum at the end of the laser pulse. The results of the correlation function analysis that we perform are confirmed by the calculations using the quantum orbits method.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and A. Schimmoller and Landsman, \{A. S.\} and Kim, \{Kyung Taec\}", note = "Publisher Copyright: {\textcopyright} 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.", year = "2024", month = apr, day = "15", doi = "10.1103/PhysRevResearch.6.023049", language = "English", volume = "6", journal = "Physical Review Research", issn = "2643-1564", publisher = "American Physical Society", number = "2", } . Physical Review Research.

Characterization of XUV+IR ionization using the circular dichroic phase @article{715aab315c444823b288289c0ee59f15, title = "Characterization of XUV+IR ionization using the circular dichroic phase", abstract = "A strong helicity dependence of reconstruction of attosecond bursts by beating of two-photon transitions (RABBITT) with circularly polarized XUV and IR pulses was reported by Han et al. [Nat. Phys. 19, 1649 (2023)1745-247310.1038/s41567-023-02188-z and arXiv:2302.04137]. They attributed a circular dichroic phase in RABBITT to the helical structure of the photoelectron wave packets in the final state. We exploit this effect to determine the magnitude and phase of two-photon XUV+IR ionization amplitudes. In s-electron targets (H, He, Li), such a determination is fully ab initio and requires no further approximations. In heavier noble gases like Ar, characterization of two-photon ionization amplitudes can be made from the circular dichroic phase with minimal and very realistic assumptions.", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2024 authors. Published by the American Physical Society.", year = "2024", month = jan, doi = "10.1103/PhysRevResearch.6.L012002", language = "English", volume = "6", journal = "Physical Review Research", issn = "2643-1564", publisher = "American Physical Society", number = "1", } . Physical Review Research.

Ivanov, I. A., Kheifets, A. S., Schimmoller, A., Landsman, A. S., Kim, Kyung Taec (2024). Evidence for nonzero electron velocity at the tunnel exit in strong-field atomic ionization . Physical Review Research.

Kheifets, Anatoli S. (2024). Characterization of XUV . Physical Review Research.

Mueller, A., Hillenbrand, P. -M, Wang, S. -X, Schippers, S., Lindroth, E., Trinter, F., Seltmann, J., Reinwardt, S., Martins, M., Kheifets, A. S., et al. (2024). Double-<i>K</i>-hole resonances in single photoionization of He-like B3+ions . Physical Review A.

Serov, Vladislav V., Kheifets, Anatoli S. (2024). Fano-line-shape metamorphosis in resonant two-photon ionization . Physical Review A.

Kheifets, Anatoli, Mathew, Albert, Kruk, Sergey, Yamada, Shunsuke, Yabana, Kazuhiro (2024). First-principles simulations of high-order harmonics generation in thin films of wide bandgap materials [Invited] . Journal of the Optical Society of America B.

Ji, Jia-Bao, Kheifets, Anatoli S., Han, Meng, Ueda, Kiyoshi, Worner, Hans Jakob (2024). Relation between photoionisation cross sections and attosecond time delays . New Journal of Physics.

Tracking quantum-cloud expansion in tunneling ionization @article{1bf16a29051d424c832fbc9ccd13e8a7, title = "Tracking quantum-cloud expansion in tunneling ionization", abstract = "We study the formation and evolution of the electron wave packets in the process of strong-field ionization of various atomic targets. Our study is based on reformulating the problem in terms of conditional amplitudes, i.e., the amplitudes describing outcomes of measurements of different observables provided that the electron is found in the ionized state after the end of the pulse. By choosing the electron coordinate as such an observable, we are able to unambiguously define the notion of the ionized wave packets and study their formation and spread. We show that the evolution of the ionized wave packets obtained in this way closely follows the classical trajectories at the initial stages of evolution providing an ab initio quantum mechanical confirmation of the basic premises of the classical Monte Carlo calculations approach. At the later stages of evolution, the picture becomes more complicated due to the wave packets' spread and due to interference of wave packets originating from different field maxima. Our approach also allows us to obtain information about the coordinate and velocity electron distributions at the tunnel exit.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Kim, \{Kyung Taec\}", note = "Publisher Copyright: {\textcopyright} 2023 American Physical Society.", year = "2023", month = nov, doi = "10.1103/PhysRevA.108.053108", language = "English", volume = "108", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "5", } . Physical Review A.

Polarization control of RABBITT in noble gas atoms @article{3891002fee7b4393a762562763b02e8c, title = "Polarization control of RABBITT in noble gas atoms", abstract = "The mutual angle formed by the non-collinear polarization axes of two laser pulses is used to control two-photon extreme ultraviolet and infrared ionization of noble gas atoms in the process of reconstruction of attosecond bursts by beating of two-photon transitions (RABBITT). The magnitude and the phase of this beating can be controlled very efficiently by the mutual polarization angle. The mechanism of this control can be understood within the lowest order perturbation theory and the soft photon approximation. We offer a very sensitive test on the polarization control of the angular dependent RABBITT process which validates our numerical simulations. We apply this test to the recent theoretical and experimental results of polarization controlled RABBITT on hydrogen and helium by Boll et al (2023 Phys. Rev. A 107 043113) and heavier noble gases by Jiang et al (2022 Nat. Commun. 13 5072).", keywords = "RABBITT, noble gas atoms, polarization control, two-photon ionization", author = "Kheifets, \{Anatoli S.\} and Zhongtao Xu", note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published by IOP Publishing Ltd.", year = "2023", month = aug, day = "14", doi = "10.1088/1361-6455/ace574", language = "English", volume = "56", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "15", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Under-threshold RABBITT in argon @article{b9ebe0922fe248d0b91373cb65b89aae, title = "Under-threshold RABBITT in argon", abstract = "The process of reconstruction of attosecond bursts by beating of two-photon transitions (RABBITT) can involve a transition from under the ionization threshold. Such an under-threshold RABBITT (or uRABBITT) was demonstrated experimentally and analyzed theoretically in He and Ne. In the present work, we explore an analogous process in the argon atom. The uRABBITT in Ar reveals the familiar physical effects: a phase transition across the threshold and the symmetry modification of the photoelectron momentum distribution. It can also be used for mapping the electronic structure of the target atom bound states.", keywords = "RABBITT, argon, under-threshold", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published by IOP Publishing Ltd.", year = "2023", month = may, day = "14", doi = "10.1088/1361-6455/acc6aa", language = "English", volume = "56", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "9", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Correlation analysis of frustrated tunneling ionization @article{582d878998e144e781dbd572313add92, title = "Correlation analysis of frustrated tunneling ionization", abstract = "We visualize frustrated tunneling ionization (FTI) using the correlation function analysis outlined in our preceding works [I. Ivanov and K. T. Kim, J. Phys. B 55, 055001 (2022)0953-407510.1088/1361-6455/ac5813; Sci. Rep. 12, 19533 (2022)2045-232210.1038/s41598-022-24168-8]. We apply this technique to the hydrogen atom subjected to a strong laser field. Our analysis supports the basic premises of the theory of FTI and demonstrates its sensitive dependence on the laser pulse duration and carrier envelope phase.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Kim, \{Kyung Taec\}", note = "Publisher Copyright: {\textcopyright} 2023 American Physical Society. ", year = "2023", month = apr, doi = "10.1103/PhysRevA.107.043106", language = "English", volume = "107", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Shape resonances in photoionization cross sections and time delay @article{feb0f6e0c3604e5aa12496ee6a4e58c3, title = "Shape resonances in photoionization cross sections and time delay", abstract = "We express the photoionization cross section of an atomic or molecular shape resonance in the form σ∝sin2δℓ which connects the cross section with the photoelectron scattering phase in the dominant partial wave ℓ. This expression allows us to relate the cross section with the photoelectron group delay (Wigner time delay) τW=∂δℓ/∂E which is measurable by recently developed laser interferometric techniques. Such a direct connection is a fundamental property of shape resonances which provides a comprehensive test of time delay measurements against a large body of older synchrotron cross-section data.", author = "Kheifets, \{Anatoli S.\} and Stephen Catsamas", note = "Publisher Copyright: {\textcopyright} 2023 American Physical Society.", year = "2023", month = feb, doi = "10.1103/PhysRevA.107.L021102", language = "English", volume = "107", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "2", } . Physical Review A.

XUV ionization of the H2 molecule studied with attosecond angular streaking @article{69c8f9da36fb479fac2e113522e4fc75, title = "XUV ionization of the H2 molecule studied with attosecond angular streaking", abstract = "We study orientation and two-center interference effects in attosecond time-resolved photoionization of the H2 molecule. Time resolution of extreme-ultraviolet ionization of H2 is gained through the phase retrieval capability of attosecond angular streaking demonstrated earlier by Kheifets et al (2022 Phys. Rev. A 106 033106). Once applied to H2, this technique delivers an anisotropic phase and time delay which both depend sensitively on the molecular axis orientation. In addition, the photoelectron momentum distribution displays a very clear two-center interference pattern. When the interference formula of Walter and Briggs (1999 J. Phys. B 32 2487) is applied, an effective photoelectron momentum appears to be greater than the asymptotic momentum at the detector. This effect is explained by a molecular potential well surrounding the photoemission center.", keywords = "molecules, photoionization, time delay", author = "Serov, \{Vladislav V.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2023 IOP Publishing Ltd.", year = "2023", month = jan, day = "28", doi = "10.1088/1361-6455/acaa23", language = "English", volume = "56", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "2", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Wigner time delay in atomic photoionization @article{0c5627c2f6dc445484ae0544671e273a, title = "Wigner time delay in atomic photoionization", abstract = "For over a century since the Nobel prize winning work by Einstein (1905 Ann. Phys. 17 132), atomic photoionization was thought to be an instantaneous process. Recent experimental advances in ultrashort laser pulse generation has allowed to resolve this process in time. The concept of time delay introduced by Wigner (1955 Phys. Rev. 98 145-7) in particle scattering appears to be central to the time resolution of photoionization. In this review, we examine the fundamental concepts of time-resolved atomic ionization processes. We will follow the recent literature and show how the initial disagreements between theory and experiment, which persisted for nearly a decade, were finally reconciled. We will also outline the exciting prospects of this field driven by modern experimental and computational technologies.", keywords = "Wigner time delay, many-electron correlation, photoionization, spectral phase, time resolution, two-color interference", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published by IOP Publishing Ltd.", year = "2023", month = jan, day = "28", doi = "10.1088/1361-6455/acb188", language = "English", volume = "56", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "2", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Propagation effects in high-harmonic generation from dielectric thin films @article{a9dd286dce7b47a491167d1a5ae533ae, title = "Propagation effects in high-harmonic generation from dielectric thin films", abstract = "A theoretical investigation is conducted of high-order harmonic generation (HHG) in silicon thin films to elucidate the effect of light propagation in reflected and transmitted waves. The first-principles simulations are performed of the process in which an intense pulsed light irradiates silicon thin films up to 3μm thickness. Our simulations are carried within the time-dependent density functional theory (TDDFT) with the account of coupled dynamics of the electromagnetic fields and the electronic motion. It was found that the intensity of transmission HHG gradually decreases with the thickness, while the reflection HHG becomes constant from a certain thickness. Detailed analyses show that transmission HHG has two origins: the HHG generated near the front edge and propagates to the back surface and the HHG generated near the back edge and emitted directly. The dominating mechanism of the transmission HHG is found to depend on the thickness of the thin film and the frequency of the HHG. At the film thickness of 1μm, the transmission HHG with the frequency below 20 eV is generated near the back edge, while that with the frequency above 20 eV is generated near the front edge and propagates from there to the back surface.", author = "Shunsuke Yamada and Tomohito Otobe and David Freeman and Anatoli Kheifets and Kazuhiro Yabana", note = "Publisher Copyright: {\textcopyright} 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.", year = "2023", month = jan, day = "15", doi = "10.1103/PhysRevB.107.035132", language = "English", volume = "107", journal = "Physical Review B", issn = "2469-9950", publisher = "American Physical Society", number = "3", } . Physical Review B.

Ivanov, I. A., Kheifets, A. S., Kim, Kyung Taec (2023). Tracking quantum-cloud expansion in tunneling ionization . Physical Review A.

Anatoli S Kheifets, Zhongtao Xu (2023). Polarization control of RABBITT in noble gas atoms . Journal of Physics B: Atomic, Molecular and Optical Physics.

Kheifets, Anatoli S. (2023). Under-threshold RABBITT in argon . Journal of Physics B: Atomic, Molecular and Optical Physics.

Ivanov, I. A., Kheifets, A. S., Kim, Kyung Taec (2023). Correlation analysis of frustrated tunneling ionization . Physical Review A.

Anatoli S Kheifets (2023). Wigner time delay in atomic photoionization . Journal of Physics B: Atomic, Molecular and Optical Physics.

Kheifets, Anatoli S., Catsamas, Stephen (2023). Shape resonances in photoionization cross sections and time delay . Physical Review A.

Serov, Vladislav V., Kheifets, Anatoli S. (2023). XUV ionization of the H-2 molecule studied with attosecond angular streaking . Journal of Physics B: Atomic, Molecular and Optical Physics.

Kheifets, Anatoli, Yamada, Shunsuke, Otobe, Tomohito, Freeman, David, Yabana, Kazuhiro (2023). Propagation effects in high-harmonic generation from dielectric thin films . Physical Review B.

Kheifets, Anatoly S(2023). Wigner time delay in atomic photoionization . Journal of Physics B: Atomic, Molecular and Optical Physics.

Interference patterns in ionization of Kramers–Henneberger atom @article{e7ce45f126a342248f996849823d7257, title = "Interference patterns in ionization of Kramers–Henneberger atom", abstract = "We combine IR pump and XUV probe laser pulses to visualize the Kramers–Henneberger (KH) state of the potassium atom. We demonstrate that ionization of such an atom exhibits some molecular-like features such as low order interference maxima in photoelectron momentum spectra. The locations of these maxima allow to estimate spatial dimensions of the KH atom and can be used for accurate calibration of high intensity laser fields. At the same time, we show that an analogy between the KH atom and a homo-nuclear diatomic molecule cannot be extended too far. In particular, higher order interference maxima are very difficult to observe in the case of the KH state. We attribute this to a particular structure of the KH potential which does not confine electron motion to a well-defined potential well unlike in real diatomic molecules.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Kim, \{Kyung Taec\}", note = "Publisher Copyright: {\textcopyright} 2022, The Author(s).", year = "2022", month = dec, doi = "10.1038/s41598-022-21549-x", language = "English", volume = "12", journal = "Scientific Reports", issn = "2045-2322", publisher = "Nature Research", number = "1", } . Scientific Reports.

Shake-Off Process in Non-Sequential Single-Photon Double Ionization of Closed-Shell Atomic Targets @article{a1f3ece699ce4f3483c4cda4e2f7d5bb, title = "Shake-Off Process in Non-Sequential Single-Photon Double Ionization of Closed-Shell Atomic Targets", abstract = "Amusia and Kheifets in 1984 introduced a Green{\textquoteright}s function formalism to describe the effect of many-electron correlation on the ionization spectra of atoms. Here, we exploit this formalism to model the shake-off (SO) process, leading to the non-sequential single-photon two-electron ionization (double photoionization—DPI) of closed-shell atomic targets. We separate the SO process from another knock-out (KO) mechanism of DPI and show the SO prevalence away from the DPI threshold. We use this kinematic regime to validate our model by making a comparison with more elaborate techniques, such as convergent and time-dependent close coupling. We also use our model to evaluate the attosecond time delay associated with the SO process. Typically, the SO is very fast, taking only a few attoseconds to complete. However, it can take much longer in the DPI of strongly correlated systems, such as the H (Formula presented.) ion as well as the subvalent shells of the Ar and Xe atoms and Cl (Formula presented.) ion.", keywords = "atomic photoionization, many-electron correlation, non-sequential double ionization", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2022 by the author.", year = "2022", month = sep, doi = "10.3390/atoms10030089", language = "English", volume = "10", journal = "Atoms", issn = "2218-2004", publisher = "Multidisciplinary Digital Publishing Institute (MDPI)", number = "3", } . Atoms.

Ionization phase retrieval by angular streaking from random shots of XUV radiation @article{2e313b60de1d43c39e0f588e5679b1e1, title = "Ionization phase retrieval by angular streaking from random shots of XUV radiation", abstract = "We demonstrate an accurate phase retrieval of extreme ultraviolet (XUV) atomic ionization by streaking the photoelectron in a circularly polarized infrared (IR) laser field. Our demonstration is based on a numerical solution of the time-dependent Schr{\"o}dinger equation. We test this technique using the hydrogen atom ionized by isolated attosecond XUV pulses across a wide range of the photon energies. Importantly, the proposed method works in a random shot mode when the time delay between the ionizing and streaking XUV and IR pulses may vary from shot to shot. This is a significant advantage over the existing interferometric techniques which require a systematic and controllable scan of the XUV and IR delay in one set of measurements. Such a scan may not be possible to take because of the arrival time jitter inherent to the stochastic nature of self-amplified free-electron laser radiation.", author = "Kheifets, \{A. S.\} and R. Wielian and Serov, \{V. V.\} and Ivanov, \{I. A.\} and Wang, \{A. Li\} and A. Marinelli and Cryan, \{J. P.\}", note = "{\textcopyright} 2022 American Physical Society", year = "2022", month = sep, doi = "10.1103/PhysRevA.106.033106", language = "English", volume = "106", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "3", } . Physical Review A.

Anatoli S. Kheifets (2022). Shake-Off Process in Non-Sequential Single-Photon Double Ionization of Closed-Shell Atomic Targets . Atoms.

High-order harmonic generation in semiconductors driven at near- and mid-infrared wavelengths @article{813c78a3cfca465db4254caec06b528c, title = "High-order harmonic generation in semiconductors driven at near- and mid-infrared wavelengths", abstract = "We study high-order harmonics generation (HHG) in crystalline silicon and diamond subjected to near- and mid-infrared laser pulses. We employ time-dependent density functional theory and solve the time-dependent Kohn-Sham equation in the single-cell geometry. We demonstrate that clear and clean HHG spectra can be generated with careful selection of the pulse duration. In addition, we simulate dephasing effects in a large silicon supercell through a displacement of atomic positions prepared by a molecular dynamics simulation. We compare our results with the previous calculations by Floss et al. [Phys. Rev. A 97, 011401(R) (2018)10.1103/PhysRevA.97.011401] on diamond at 800 nm and by Tancogne-Dejean et al. [Phys. Rev. Lett. 118, 087403 (2017)10.1103/PhysRevLett.118.087403] on Si at 3000 nm.", author = "David Freeman and Anatoli Kheifets and Shunsuke Yamada and Atsushi Yamada and Kazuhiro Yabana", note = "Publisher Copyright: {\textcopyright} 2022 American Physical Society.", year = "2022", month = aug, day = "15", doi = "10.1103/PhysRevB.106.075202", language = "English", volume = "106", journal = "Physical Review B", issn = "2469-9950", publisher = "American Physical Society", number = "7", } . Physical Review B.

Dynamic extension of the Keldysh-Rutherford model for attoclocks @article{659fd93efe98470999f057cdab5bcee7, title = "Dynamic extension of the Keldysh-Rutherford model for attoclocks", abstract = "The classical Keldysh-Rutherford (KR) model of the attoclock [A. W. Bray et al., Phys. Rev. Lett. 121, 123201 (2018)0031-900710.1103/PhysRevLett.121.123201] was introduced to interpret attosecond angular streaking on atomic hydrogen in the low laser intensity regime. In this model, the photoelectron acquires its final velocity immediately after exiting the tunnel and then scatters elastically on the Coulomb field of the residual ion. In the present work, we make a dynamic extension of the KR model and consider a gradual acceleration of the photoelectron by the driving laser field. By doing so, we observe and explain a significant displacement of the peaks of the angular distribution of the mean photoelectron momentum and the angular resolved ionization probability. These peaks should be close within the original KR model.", author = "Serov, \{Vladislav V.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2022 American Physical Society.", year = "2022", month = jun, doi = "10.1103/PhysRevA.105.063106", language = "English", volume = "105", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Taking the Convergent Close-Coupling Method beyond Helium @article{fef639893e6943509a4087658863b287, title = "Taking the Convergent Close-Coupling Method beyond Helium: The Utility of the Hartree-Fock Theory", abstract = "The convergent close-coupling (CCC) method was initially developed to describe electron scattering on atomic hydrogen and the hydrogenic ions such as He+. The latter allows implementation of double photoionization (DPI) of the helium atom. For more complex single valence-electron atomic and ionic targets, the direct and exchange interaction with the inner electron core needs to be taken into account. For this purpose, the Hartree-Fock (HF) computer codes developed in the group of Miron Amusia have been adapted. In this brief review article, we demonstrate the utility of the HF technique by examples of electron scattering on Li and the DPI of the H− and Li− ions. We also discuss that modern-day computer infrastructure allows the associated CCC code, and others, to be readily run directly via the Atomic, Molecular and Optical Science Gateway.", keywords = "Atomic photoionization, Electronic structure, Electron–atom scattering, Many-electron correlation", author = "Igor Bray and Xavier Weber and Fursa, \{Dmitry V.\} and Kadyrov, \{Alisher S.\} and Schneider, \{Barry I.\} and Sudhakar Pamidighantam and Maciej Cytowski and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2022 by the authors. Licensee MDPI, Basel, Switzerland.", year = "2022", month = mar, doi = "10.3390/atoms10010022", language = "English", volume = "10", journal = "Atoms", issn = "2218-2004", publisher = "Multidisciplinary Digital Publishing Institute (MDPI)", number = "1", } . Atoms.

Igor Bray, Xavier Weber, Dmitry V. Fursa, Alisher S. Kadyrov, Barry I. Schneider, Sudhakar Pamidighantam, Maciej Cytowski, Anatoli S. Kheifets (2022). Taking the Convergent Close-Coupling Method beyond Helium: The Utility of the Hartree-Fock Theory . Atoms.

Symmetry analysis of the photoelectron continuum in two-photon XUV + IR ionization @article{f4ee4015df684e44b1b747076e9364be, title = "Symmetry analysis of the photoelectron continuum in two-photon XUV + IR ionization", abstract = "The photoelectron momentum distribution (PMD) in two-photon XUV-IR ionization of Ne is studied theoretically by numerical solution of the time-dependent Schr{\"o}dinger equation and within the analytical soft photon approximation. The symmetry of the PMD, projected on the plane encompassing the joint XUV-IR linear polarization axis, reveals the angular momentum composition of the photoelectron wave packet. This composition, in turn, allows to examine the validity of the angular momentum propensity rules which govern the bound-continuum and continuum-continuum photon driven transitions. The Fano propensity rule for bound-continuum transitions that favors an increase in the angular momentum is confirmed. However, its extension to continuum-continuum transitions suggested by Busto [Phys. Rev. Lett. 123, 133201 (2019)PRLTAO0031-900710.1103/PhysRevLett.123.133201] is less straightforward. In addition, we break the time-reversal symmetry of the XUV field by combining the odd and even multiples of the fundamental frequency. By doing so, we change the time and angular structure of the photoelectron continuum.", author = "Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2022 American Physical Society.", year = "2022", month = jan, doi = "10.1103/PhysRevA.105.013114", language = "English", volume = "105", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Ivanov, I. A., Kheifets, A. S., Kyung Taec Kim (2022). Interference patterns in ionization of Kramers-Henneberger atom . Scientific Reports.

Kheifets, A. S., Wielian, R., Serov, V. V., Ivanov, I. A., Li Wang, A., Marinelli, A., Cryan, J. P. (2022). Ionization phase retrieval by angular streaking from random shots of XUV radiation . Physical Review A.

(2022). Symmetry analysis of the photoelectron continuum in two-photon XUV plus IR ionization . Physical Review A.

Serov, Vladislav V, Kheifets, Anatoly S(2022). XUV ionization of the H2 molecule studied with attosecond angular streaking . Journal of Physics B: Atomic, Molecular and Optical Physics.

(2022). Shake-Off Process in Non-Sequential Single-Photon Double Ionization of Closed-Shell Atomic Targets .

Kheifets, Anatoli, Freeman, David, Yamada, Shunsuke, Yamada, Atsushi, Yabana, Kazuhiro (2022). High-order harmonic generation in semiconductors driven at near- and mid-infrared wavelengths . Physical Review B.

Serov, Vladislav V., Kheifets, Anatoli S. (2022). Dynamic extension of the Keldysh-Rutherford model for attoclocks . Physical Review A.

Bray, Igor, Weber, Xavier, Fursa, Dmitry, V, Kadyrov, Alisher S., Schneider, Barry, I, Pamidighantam, Sudhakar, Cytowski, Maciej, Kheifets, Anatoli S. (2022). Taking the Convergent Close-Coupling Method beyond Helium: The Utility of the Hartree-Fock Theory . Atoms.

Role of nuclear-electronic coupling in attosecond photoionization of H2 @article{97a77b31ec734fb8a072d6be611b0822, title = "Role of nuclear-electronic coupling in attosecond photoionization of H2", abstract = "The separation of electronic and nuclear dynamics due to differing timescales is a useful concept for understanding ground-state molecular systems. However, coupling between these degrees of freedom is critical to understanding the evolution of most excited-state systems. We measure two-photon ionization delays of H2 and compare to calculations of the same measurement in a frozen-nuclei approximation. We find discrepancies between the vibrationally resolved measurement and bond-length-dependent theory, suggesting that nuclear motion affects H2 photoionization on attosecond timescales. We ascribe our observation to nuclear-electronic channel coupling between continuum vibrational states. Our results demonstrate that nuclear-electronic coupling cannot be neglected in the sudden ionization of molecules containing light atoms.", author = "Wang, \{Anna L.\} and Serov, \{Vladislav V.\} and Andrei Kamalov and Bucksbaum, \{Philip H.\} and Anatoli Kheifets and Cryan, \{James P.\}", note = "Publisher Copyright: Published by the American Physical Society", year = "2021", month = dec, doi = "10.1103/PhysRevA.104.063119", language = "English", volume = "104", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Effect of the finite speed of light in ionization of extended molecular systems @article{a3faed83ab1940079a5382708621b61e, title = "Effect of the finite speed of light in ionization of extended molecular systems", abstract = "We study propagation effects due to the finite speed of light in ionization of extended molecular systems. We present a general quantitative theory of these effects and show under which conditions such effects should appear. The finite speed of light propagation effects are encoded in the non-dipole terms of the time-dependent Shr{\"o}dinger equation and display themselves in the photoelectron momentum distribution projected on the molecular axis. Our numerical modeling for the H2+ molecular ion and the Ne 2 dimer shows that the finite light propagation time from one atomic center to another can be accurately determined in a table top laser experiment which is much more readily accessible than the ground breaking synchrotron measurement by Grundmann et al. (Science 370:339, 2020).", author = "Ivanov, \{I. A.\} and Kheifets, \{Anatoli S.\} and Kim, \{Kyung Taec\}", note = "Publisher Copyright: {\textcopyright} 2021, The Author(s).", year = "2021", month = dec, doi = "10.1038/s41598-021-00818-1", language = "English", volume = "11", journal = "Scientific Reports", issn = "2045-2322", publisher = "Nature Research", number = "1", } . Scientific Reports.

Time delay in two-electron photodetachment and tests of fundamental threshold laws @article{51c99183231e4cc7b6b97b0ec282008e, title = "Time delay in two-electron photodetachment and tests of fundamental threshold laws", abstract = "The photoelectron group delay, also known as the Wigner time delay (WTD), is examined in photodetachment of the and ions near their lowest inelastic and the double detachment thresholds. These threshold processes promoting the remaining bound electron to an excited state or ejecting it to the continuum involve two active electrons and are termed collectively two-electron photodetachment. The opening of an inelastic channel is governed by the Wigner threshold law which affects the WTD very differently in and . At the same time, the Wannier threshold behavior of the WTD in double detachment is similar in both targets. Experimental verification of these theoretical predictions will subject the Wigner and Wannier threshold laws to a set of stringent tests in the time domain.", author = "Kheifets, \{Anatoli S.\} and I. Bray", note = "Publisher Copyright: {\textcopyright} 2021 Published by the American Physical Society", year = "2021", month = dec, doi = "10.1103/PhysRevResearch.3.043017", language = "English", volume = "3", journal = "Physical Review Research", issn = "2643-1564", publisher = "American Physical Society", number = "4", } . Physical Review Research.

Revealing the target electronic structure with under-threshold rabbiitt @article{1eecd799d0c94e128397d7a4707d20d7, title = "Revealing the target electronic structure with under-threshold rabbiitt", abstract = "The process of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) reveals the target atom electronic structure when one of the transitions proceeds from below the ionization threshold. Such an under-threshold RABBITT resonates with the target bound states and thus maps faithfully the discrete energy levels and the corresponding oscillator strengths. We demonstrate this sensitivity by considering the Ne atom driven by the combination of the XUV and IR pulses at the fundmanetal laser frequency in the 800 and 1000 nm ranges.", keywords = "Atomic photoionization, Electronic structure, Multiphoton processes", author = "Anatoli Kheifets", note = "Publisher Copyright: {\textcopyright} 2021 by the author. Licensee MDPI, Basel, Switzerland.", year = "2021", month = sep, doi = "10.3390/atoms9030066", language = "English", volume = "9", journal = "Atoms", issn = "2218-2004", publisher = "Multidisciplinary Digital Publishing Institute (MDPI)", number = "3", } . Atoms.

Two-pulse interference and correlation in an attoclock @article{e3f49d82a1cc460eb82f6db0b1b95249, title = "Two-pulse interference and correlation in an attoclock", abstract = "We study cross correlation of a single-cycle circularly polarized laser pulse with its delayed and/or attenuated replica in the attoclock field configuration. In this configuration, tunneling ionization of the target atom is observed in the polarization plane of the driving laser pulse. The two-pulse attoclock displays a robust interference pattern in the photoelectron energy spectrum and the real time correlation between the photon absorption rates from the two pulses. This interference and correlation can be used for characterization of single-cycle laser pulses and monitoring the target population dynamics during the ionization process.", author = "Kheifets, \{Anatoli S.\} and Joshua Cesca and Serov, \{Vladislav V.\} and Kim, \{Kyung Taec\} and Ivanov, \{Igor A.\}", note = "Publisher Copyright: {\textcopyright} 2021 American Physical Society.", year = "2021", month = sep, doi = "10.1103/PhysRevA.104.033118", language = "English", volume = "104", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "3", } . Physical Review A.

Role of L-shell single and double core-hole production and decay in m-fold (1=m=6) photoionization of the Ar+ ion @article{37a460adcc4d448db5ffbf6e4bdd4ca2, title = "Role of L-shell single and double core-hole production and decay in m-fold (1=m=6) photoionization of the Ar+ ion", abstract = "Multiple ionization of the Ar+(3s23p5) ion by a single photon has been investigated in the photon-energy range 250-1800 eV employing the photon-ion merged-beams technique. Absolute partial cross sections were measured for all Ar(1+m)+ product-ion channels with 1≤m≤6 covering a size range from several tens of Mb down to a few b. Narrow 2p-subshell excitation resonances were observed in all channels up to quadruple ionization at a photon-energy bandwidth of 52 meV. Double excitations involving a 2p and a 3s or 3p electron were also studied at high resolution and the measurements of the broad 2s excitation resonances directly showed their natural widths. Contributions of direct photo double ionization (PDI) to the production of the highest final Ar ion charge states are revealed, with PDI of the 2s subshell being mainly responsible for the production of Ar7+. The experiment made use of the PIPE setup installed at beamline P04 of the PETRA III synchrotron light source of DESY in Hamburg. The measurements were supported by theoretical calculations to identify the main contributions to the observed cross sections. Comparisons of theory and experiment show remarkable agreement but also hint to additional ionization mechanisms that are not considered in the theoretical models such as core ionization accompanied by excitations with subsequent Auger decays leading to net m-fold ionization with m≥4.", author = "A. M{\"u}ller and M. Martins and A. Borovik and T. Buhr and A. Perry-Sassmannshausen and S. Reinwardt and F. Trinter and S. Schippers and S. Fritzsche and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2021 American Physical Society.", year = "2021", month = sep, doi = "10.1103/PhysRevA.104.033105", language = "English", volume = "104", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "3", } . Physical Review A.

Strongly resonant reconstruction of attosecond beating by interference of two-photon transitions on lithium @article{f4bcccd7897d46c7b1ced6d9758aa356, title = "Strongly resonant reconstruction of attosecond beating by interference of two-photon transitions on lithium", abstract = "The process of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) can become resonant with a discrete atomic level either in the intermediate or the final continuous states. Experimental observations of the former [Phys. Rev. Lett. 104, 103003 (2010)PRLTAO0031-900710.1103/PhysRevLett.104.103003] and latter [Nature Commun. 7, 10566 (2016)10.1038/ncomms10566] resonant processes revealed modification of only those parts of the photoelectron spectrum that overlapped directly with the resonance. In the lithium atom and other members of the alkali-metal family, the valence shell ns→np transition to the intermediate RABBITT state affects the whole photoelectron spectrum in the final state. The strong additional resonant channel modifies entirely the ionization dynamics and opens direct access to the resonant phase of the two-photon transitions, which is common for various single and multiple electron ionization processes. Elucidation of this phase has wider implications for strongly resonant laser-matter interaction.", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2021 American Physical Society.", year = "2021", month = aug, doi = "10.1103/PhysRevA.104.L021103", language = "English", volume = "104", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "2", } . Physical Review A.

Direct double ionization of the Ar+ M shell by a single photon @article{0813c7e5531940c08ceb5f96c3f254e6, title = "Direct double ionization of the Ar+ M shell by a single photon", abstract = "Direct double ionization of the Ar+(3p-1) ion by a single photon is investigated both experimentally and theoretically. The photon-ion merged-beams technique was employed at the Advanced Light Source in Berkeley, USA, to measure absolute cross sections in the energy range from 60 to 150 eV. In this range, three contributions to the double ionization of Ar+ are to be expected: the removal of two 3p electrons, of a 3s and a 3p electron, and of two 3s electrons. Among the possible mechanisms leading to double ionization, the TS1 (two-step one) process dominates in the near-threshold region. In TS1, a photoelectron is ejected and, on its way out, knocks out a secondary electron. This two-step mechanism is treated theoretically by multiplying the calculated cross section for direct single photoionization of a given subshell with the calculated (e,2e) ionization probability for the ejected photoelectron to knock off a secondary electron. The calculated cross section is in very good agreement with the experiment.", author = "A. M{\"u}ller and Kilcoyne, \{A. L.D.\} and Phaneuf, \{R. A.\} and K. Holste and S. Schippers and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2021 American Physical Society.", year = "2021", month = mar, doi = "10.1103/PhysRevA.103.L031101", language = "English", volume = "103", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "3", } . Physical Review A.

Numerical and laboratory attoclock simulations on noble-gas atoms @article{8869e6bcc08c4d79b501a21d53b71fd4, title = "Numerical and laboratory attoclock simulations on noble-gas atoms", abstract = "We conduct a systematic theoretical study of strong field tunneling ionization of noble-gas atoms, from He to Kr, by elliptically polarized laser pulses in the so-called attoclock setup. Our theoretical model is based on a numerical solution of the time-dependent Schr{\"o}dinger equation in the single active electron approximation. We simulate laboratory measurements utilizing few optical cycle pulses to benchmark our calculations against experiment. We further conduct {"}numerical attoclock{"}simulations with short, nearly single-cycle pulses to test various tunneling ionization models. We examine the attoclock offset angles as affected by the target orbital structure and the laser pulse intensity. Finally, we exclude a finite tunneling time scenario and attribute the attoclock offset angle entirely to the Coulomb field of the ion remainder as was recently demonstrated for the hydrogen atom [U. S. Sainadh, Nature (London) 568, 75 (2019)NATUAS0028-083610.1038/s41586-019-1028-3].", author = "Serov, \{Vladislav V.\} and Joshua Cesca and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2021 American Physical Society.", year = "2021", month = feb, doi = "10.1103/PhysRevA.103.023110", language = "English", volume = "103", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "2", } . Physical Review A.

RABBITT phase transition across the ionization threshold @article{fa3b0454466b4cf2a4f51b0b0fe64122, title = "RABBITT phase transition across the ionization threshold", abstract = "Rich physics emerges as the result of interplay between discrete and continuous quantum states. A process of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) reveals a similar phenomenon. In RABBITT, primary XUV driven ionization is aided by secondary IR photon absorption or emission. The latter processes involve transitions between continuous states. We demonstrate that when RABBITT crosses the ionization threshold and proceeds via a discrete bound state, its phase makes a sudden jump which can be related to the phase of the continuous transitions above the threshold. Up to now, this phase remained undetermined experimentally and could only be estimated theoretically. The under-threshold RABBITT provides alternative means of assessing this quantity.", author = "Kheifets, \{Anatoli S.\} and Bray, \{Alexander W.\}", note = "Publisher Copyright: {\textcopyright} 2021 American Physical Society.", year = "2021", month = jan, doi = "10.1103/PhysRevA.103.L011101", language = "English", volume = "103", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Ivanov, I. A., Kheifets, Anatoli S., Kim, Kyung Taec (2021). Effect of the finite speed of light in ionization of extended molecular systems . Scientific Reports.

Kheifets, Anatoli, Wang, Anna L., Serov, Vladislav V., Kamalov, Andrei, Bucksbaum, Philip H., Cryan, James P. (2021). Role of nuclear-electronic coupling in attosecond photoionization of H-2 . Physical Review A.

Kheifets, Anatoli S., Bray, I (2021). Time delay in two-electron photodetachment and tests of fundamental threshold laws . Physical Review Research.

Anatoli Kheifets (2021). Revealing the Target Electronic Structure with Under-Threshold RABBITT . Atoms.

Mueller, A., Martins, M., Borovik, A., Jr., Buhr, T., Perry-Sassmannshausen, A., Reinwardt, S., Trinter, F., Schippers, S., Fritzsche, S., Kheifets, A. S. (2021). Role of <i>L</i>-shell single and double core-hole production and decay in <i>m</i>-fold (1 ≤ <i>m</i> ≤ 6) photoionization of the Ar<SUP>+</SUP> ion . Physical Review A.

(2021). Strongly resonant reconstruction of attosecond beating by interference of two-photon transitions on lithium . Physical Review A.

Kheifets, Anatoli S., Cesca, Joshua, Serov, Vladislav V., Kim, Kyung Taec, Ivanov, Igor A. (2021). Two-pulse interference and correlation in an attoclock . Physical Review A.

Mueller, A., Kilcoyne, A. L. D., Phaneuf, R. A., Holste, K., Schippers, S., Kheifets, A. S. (2021). Direct double ionization of the Ar<SUP>+</SUP> <i>M</i> shell by a single photon . Physical Review A.

Serov, Vladislav V., Cesca, Joshua, Kheifets, Anatoli S. (2021). Numerical and laboratory attoclock simulations on noble-gas atoms . Physical Review A.

Kheifets, Anatoli S., Bray, Alexander W. (2021). RABBITT phase transition across the ionization threshold . Physical Review A.

Revealing the two-electron cusp in the ground states of He and H2 via quasifree double photoionization @article{ccd4529782ae4d8d8241306107b8969d, title = "Revealing the two-electron cusp in the ground states of He and H2 via quasifree double photoionization", abstract = "We report on kinematically complete measurements and ab initio nonperturbative calculations of double ionization of He and H2 by a single 800 eV circularly polarized photon. We confirm the quasifree mechanism of photoionization for H2 and show how it originates from the two-electron cusp in the ground state of a two-electron target. Our approach establishes a method for mapping electrons relative to each other and provides valuable insight into photoionization beyond the electric-dipole approximation.", author = "Sven Grundmann and Serov, \{Vladislav V.\} and Florian Trinter and Kilian Fehre and Nico Strenger and Andreas Pier and Max Kircher and Daniel Trabert and Miriam Weller and Jonas Rist and Leon Kaiser and Bray, \{Alexander W.\} and Schmidt, \{Lothar Ph H.\} and Williams, \{Joshua B.\} and Till Jahnke and Reinhard D{\"o}rner and Sch{\"o}ffler, \{Markus S.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.", year = "2020", month = jul, doi = "10.1103/PhysRevResearch.2.033080", language = "English", volume = "2", journal = "Physical Review Research", issn = "2643-1564", publisher = "American Physical Society", number = "3", } . Physical Review Research.

Angular dependent time delay near correlation induced Cooper minima @article{ead9df98b0f1458a9b02c7f3ff67f924, title = "Angular dependent time delay near correlation induced Cooper minima", abstract = "We analyze an angular dependence of the Wigner time delay near the Cooper minimum (CM) of the sub-valent ns shell in argon, krypton and xenon. Such an angular dependence is a result of interplay between the relativistic and correlation effects. The correlation with the outermost np valence shell induces a CM in the sub-valent ns shell which is otherwise CM free. A phase difference between the two spin-orbit split ionization continua Ep 1/2 and Ep 3/2 makes the Wigner time delay angular dependent. Both these effects are accounted for within relativistic formulations of the random phase approximation and the time-dependent density functional theory. Comparison between these two approaches illustrates a very strong sensitivity of the observed effect to the computation detail, especially the account of the ground state correlation.", author = "Kheifets, \{Anatoli S.\} and Daniele Toffoli and Piero Decleva", note = "Publisher Copyright: {\textcopyright} 2020 IOP Publishing Ltd.", year = "2020", month = jun, day = "14", doi = "10.1088/1361-6455/ab78aa", language = "English", volume = "53", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "11", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Effects of relativistic interactions in photodetachment time delay of Br- @article{b3f4e50030594e9eb360ef8818be9cb1, title = "Effects of relativistic interactions in photodetachment time delay of Br-", abstract = "Wigner time delay in photodetachment of Br-has been studied. The absence of Coulomb phase in photodetachment process makes the Wigner time delay more sensitive to the centrifugal barrier shape resonance and threshold effects. Important relativistic effects have been found near the threshold region.", author = "S. Saha and J. Jose and Deshmukh, \{P. C.\} and Kheifets, \{A. S.\} and Dolmatov, \{V. K.\} and Manson, \{S. T.\}", note = "Publisher Copyright: {\textcopyright} 2020 Journal of Physics: Conference Series. All rights reserved.; 31st International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2019 ; Conference date: 23-07-2019 Through 30-07-2019", year = "2020", month = jun, day = "11", doi = "10.1088/1742-6596/1412/9/092013", language = "English", volume = "1412", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Attosecond angular streaking on H2 with all-ionic fragments detection @article{4efd83bdab1b4216a312bdd08f3686c2, title = "Attosecond angular streaking on H2 with all-ionic fragments detection", abstract = "We explore a novel attosecond angular streaking scheme on H2 based on the all-ionic dissociative fragments detection. We aim to reveal the same information from the ionic attoclock as extracted from conventional attoclock measurements [1]. We examine the validity of the axial recoil approximation questioned in [2]. The advantage of the proposed scheme is that it does not rely on the adiabatic electron tunneling hypothesis which has raised the ongoing controversy of a finite tunneling time in the attosecond community [3].", author = "W. Quan and M. Zhao and Serov, \{V. V.\} and Wei, \{M. Z.\} and Y. Zhou and Lai, \{X. Y.\} and Kheifets, \{A. S.\} and Liu, \{X. J.\}", note = "Publisher Copyright: {\textcopyright} 2019 Published under licence by IOP Publishing Ltd.; 31st International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2019 ; Conference date: 23-07-2019 Through 30-07-2019", year = "2020", month = jun, day = "11", doi = "10.1088/1742-6596/1412/7/072043", language = "English", volume = "1412", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "7", } . Journal of Physics: Conference Series.

Correlation-enhanced high-order-harmonic-generation spectra of Mn and Mn+ @article{63a56d8f077f42eabf623794a9ab64b5, title = "Correlation-enhanced high-order-harmonic-generation spectra of Mn and Mn+", abstract = "We examine giant resonant enhancement of high-order harmonics generation (HHG) in the Mn atom and its singly charged Mn+ ion. Our theoretical model combines single active electron tunneling and propagation with correlation-enhanced recombination. Previously, this approach demonstrated its useability for the Xe atom [Phys. Rev. A 100, 013404 (2019)2469-992610.1103/PhysRevA.100.013404]. Spin-polarized Hartree-Fock and random-phase approximation with exchange calculations are carried out to evaluate the correlation enhancement factor in Mn and Mn+, which is then compared with other reported calculations and the experiment.", author = "Bray, \{Alexander W.\} and David Freeman and Faiza Naseem and Dolmatov, \{Valeriy K.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2020 American Physical Society.", year = "2020", month = may, doi = "10.1103/PhysRevA.101.053415", language = "English", volume = "101", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "5", } . Physical Review A.

The attoclock and the tunneling time debate @article{2dd19f6a8d1c4e76bd05a5a3bb589624, title = "The attoclock and the tunneling time debate", abstract = "Attosecond angular streaking, also known as the 'attoclock', employs a short elliptically polarized laser pulse to tunnel ionize an electron from an atom or a molecule and to put a time stamp on this process by deflecting the photoelectron in the angular spatial direction. This deflection can be used to evaluate the time the tunneling electron spends under the classically inaccessible barrier and to determine whether this time is finite. In this review, we examine the latest experimental and theoretical findings and present a comprehensive set of evidence supporting the zero tunneling time scenario.", keywords = "Wigner time, attoclock, attosecond science, tunneling ionization", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2020 IOP Publishing Ltd.", year = "2020", month = apr, day = "14", doi = "10.1088/1361-6455/ab6b3b", language = "English", volume = "53", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "7", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Effects of spin-orbit-interaction-activated interchannel coupling on photoemission time delay @article{a231b72a169142f9819d8ed30dffc7c1, title = "Effects of spin-orbit-interaction-activated interchannel coupling on photoemission time delay", abstract = "Spin-orbit-interaction-activated interchannel coupling (SOIAIC) has been investigated theoretically in the time delay domain for 3d photoemission in the isoelectronic sequence I-, Xe, and Cs+ using the relativistic-random-phase approximation with relaxation. The results show that SOIAIC becomes more important with increasing nuclear charge, and that time delay is affected more strongly than cross sections or photoelectron angular distribution β parameters.", author = "Sourav Banerjee and Deshmukh, \{Pranawa C.\} and Kheifets, \{Anatoli S.\} and Manson, \{Steven T.\}", note = "Publisher Copyright: {\textcopyright} 2020 American Physical Society.", year = "2020", month = apr, doi = "10.1103/PhysRevA.101.043411", language = "English", volume = "101", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Time correlation inside a laser pulse @article{49ddc720a6a7484594873c99c256aa9d, title = "Time correlation inside a laser pulse", abstract = "Looking inside a laser pulse by detecting an instantaneous ionization rate (IIR) has been a useful instrument for characterizing subcycle ionization dynamics [Phys. Rev. A 64, 013409 (2001)PLRAAN1050-294710.1103/PhysRevA.64.013409]. However, this instrument relies entirely on IIR being a deterministic function of time. By introducing an IIR operator and studying its autocorrelation function, we show that electron ionization dynamics is more complex and the ionization rate depends on the {"}prehistory,{"} i.e., the IIRs at the two instants of time are, in fact, correlated. The pattern of this correlation changes dramatically between the multiphoton and tunneling ionization regimes. These findings have wide implications for strong-field atomic physics and providing new possibilities for quantum local realism tests.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Kim, \{Kyung Taec\}", note = "Publisher Copyright: {\textcopyright} 2020 American Physical Society.", year = "2020", month = apr, doi = "10.1103/PhysRevA.101.043407", language = "English", volume = "101", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Dynamic scaling of photo-double-ionization to electron impact @article{d8d3a97defdd46e6b401d030dba4141c, title = "Dynamic scaling of photo-double-ionization to electron impact", abstract = "We employ an ab initio theory to address several inconsistencies of the empirical scaling of photo-double-ionization (PDI) to electron impact ionization suggested by Samson [Phys. Rev. Lett. 65, 2861 (1990)10.1103/PhysRevLett.65.2861]. We do so (i) by isolating the only relevant dipole component of the electron impact ionization and (ii) by replacing the static scaling of Samson, who used an effective cross-section area of the ion remainder, with dynamic scaling using the squared momentum of the photoelectron. The modified scaling is tested in the He 1s2 isoelectronic sequence and the combined inner shell 1s and valence shell 2p PDI of the negative F-ion [M{\"u}ller et al., Phys. Rev. Lett. 120, 133202 (2018)10.1103/PhysRevLett.120.133202].", author = "Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2020 American Physical Society.", year = "2020", month = mar, doi = "10.1103/PhysRevA.101.032701", language = "English", volume = "101", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "3", } . Physical Review A.

Grundmann, Sven, Serov, Vladislav V., Trinter, Florian, Fehre, Kilian, Strenger, Nico, Pier, Andreas, Kircher, Max, Trabert, Daniel, Weller, Miriam, Rist, Jonas, et al. (2020). Revealing the two-electron cusp in the ground states of He and H₂ via quasifree double photoionization . Physical Review Research.

Kheifets, Anatoli S., Toffoli, Daniele, Decleva, Piero (2020). Angular dependent time delay near correlation induced Cooper minima . Journal of Physics B: Atomic, Molecular and Optical Physics.

Kheifets, Anatoli S. (2020). The attoclock and the tunneling time debate . Journal of Physics B: Atomic, Molecular and Optical Physics.

Bray, Alexander W., Freeman, David, Naseem, Faiza, Dolmatov, Valeriy K., Kheifets, Anatoli S. (2020). Correlation-enhanced high-order-harmonic-generation spectra of Mn and Mn+ . Physical Review A.

Banerjee, Sourav, Deshmukh, Pranawa C., Kheifets, Anatoli S., Manson, Steven T. (2020). Effects of spin-orbit-interaction-activated interchannel coupling on photoemission time delay . Physical Review A.

Ivanov, I. A., Kheifets, A. S., Kim, Kyung Taec (2020). Time correlation inside a laser pulse . Physical Review A.

Kheifets, Anatoli S. (2020). Dynamic scaling of photo-double-ionization to electron impact . Physical Review A.

Attosecond Molecular Angular Streaking with All-Ionic Fragments Detection @article{9e1ba4be66884f1e9adb8feb9090f407, title = "Attosecond Molecular Angular Streaking with All-Ionic Fragments Detection", abstract = "Attosecond angular streaking (or {"}attoclock{"}) is an insightful technique for probing the ultrafast electron dynamics in strong laser fields. Up until recently, this technique relied solely on an accurate measurement of the photoelectron momentum distribution and has remained restricted to atomic targets. Here, we propose a novel attosecond angular streaking scheme applicable to molecules, for which the ionic fragments of dissociative ionization are detected in the polarization plane of a close-to-circular polarized laser light. Our ionic attoclock measurements are consistent with theoretical results from a numerical solution of the time-dependent Schr{\"o}dinger equation and an upper bound of 10 as on the tunneling time from the attoclock readings in the H2 molecule has been given, which is significantly smaller than any definitions of tunneling time available in the literatures.", author = "Wei Quan and Serov, \{Vladislav V.\} and Wei, \{Ming Zheng\} and Meng Zhao and Yu Zhou and Wang, \{Yan Lan\} and Lai, \{Xuan Yang\} and Kheifets, \{Anatoli S.\} and Liu, \{Xiao Jun\}", note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.", year = "2019", month = nov, day = "26", doi = "10.1103/PhysRevLett.123.223204", language = "English", volume = "123", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "22", } . Physical Review Letters.

Correlation enhancement of high-order harmonic generation in Xe @article{b01d2be21eee4de5a68b5ef33dd1a0a2, title = "Correlation enhancement of high-order harmonic generation in Xe", abstract = "We consider the process of high-order harmonics generation (HHG) in the xenon atom enhanced by the intershell correlation between the valence 5p and inner 4d shells. We derive the HHG spectrum from a numerical solution of the one-electron time-dependent Schr{\"o}dinger equation multiplied by the enhancement factor taken as the photoionization cross-sections ratio calculated with and without the intershell correlation. Such a simplified approach is adequate to describe the experimental HHG spectrum reported by Shiner et al. [Nat. Phys. 7, 464 (2011)1745-247310.1038/nphys1940] generated by a single color IR laser. Similarly, we find good agreement when applied to the two-color driven HHG spectra reported by Faccial{\'a} et al. [Phys. Rev. Lett. 117, 093902 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.093902].", author = "Bray, \{Alexander W.\} and David Freeman and Sebastian Eckart and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.", year = "2019", month = jul, day = "9", doi = "10.1103/PhysRevA.100.013404", language = "English", volume = "100", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Numerical attoclock on atomic and molecular hydrogen @article{82dad61b63d349f194bb5729f368b78e, title = "Numerical attoclock on atomic and molecular hydrogen", abstract = "Numerical attoclock is a theoretical model of attosecond angular streaking driven by a very short, nearly a single oscillation, circularly polarized laser pulse. The reading of such an attoclock is readily obtained from a numerical solution of the time-dependent Schr{\"o}dinger equation as well as a semiclassical trajectory simulation. By comparing the two approaches, we highlight the essential physics behind the attoclock measurements. In addition, we analyze the predictions of the Keldysh-Rutherford model of the attoclock [A. W. Bray, Phys. Rev. Lett. 121, 123201 (2018)10.1103/PhysRevLett.121.123201]. In molecular hydrogen, we highlight a strong dependence of the width of the attoclock angular peak on the molecular orientation and attribute it to the two-center electron interference. This effect is further exemplified in the weakly bound neon dimer.", author = "Serov, \{Vladislav V.\} and Bray, \{Alexander W.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.", year = "2019", month = jun, day = "27", doi = "10.1103/PhysRevA.99.063428", language = "English", volume = "99", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Dominance of correlation and relativistic effects on photodetachment time delay well above threshold @article{284347050a7f44edb567f94e95ef3a3f, title = "Dominance of correlation and relativistic effects on photodetachment time delay well above threshold", abstract = "Wigner time delay in photodetachment from the 3p3/2 and 3p1/2 subshells of Cl- has been studied in the vicinity of the 2p3/2 and 2p1/2 thresholds, using the relativistic random phase approximation (RRPA). The results show time delay spectra dominated by many-body correlations along with very complicated dependence on the energy over a broad spectral range. In addition, the time delay spectra of the two spin-orbit split 3p subshells differ significantly from one another, thereby revealing the importance of relativistic effects even in the case of a low-Z system.", author = "Soumyajit Saha and Deshmukh, \{Pranawa C.\} and Kheifets, \{Anatoli S.\} and Manson, \{Steven T.\}", note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.", year = "2019", month = jun, day = "17", doi = "10.1103/PhysRevA.99.063413", language = "English", volume = "99", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Wigner time delay in photodetachment @article{bd3d4b6c9f744fd8bf349e21531d80dd, title = "Wigner time delay in photodetachment", abstract = "Using Cl- as a test case, Wigner time delay in the photodetachment process has been investigated theoretically, along with the photoionization of the isoelectronic Ar atom, for the outer 3p shell using the relativistic-random-phase approximation (RRPA). Time delay was probed in these systems from threshold to 80 eV, to investigate threshold effects, the centrifugal barrier shape resonance, and the Cooper minimum region. This study focuses on Cl- because, for negative ions, the phase of the photoemission process is not dominated by the Coulomb phase as it is in photoionization. The results show significant differences, both qualitative and quantitative, between the time delays for Cl- and Ar photoemission at low photoelectron energy, but they are rather similar in the Cooper minimum region, where the Coulomb phase is small. In particular, the Wigner time delay in Cl- exhibits a dramatic energy dependence just above threshold, and a rapidly increasing time delay in the vicinity of the shape resonance. A strong angular dependence of time delay has also been found near the threshold region for the Cl- case, and is absent in the case of the photoionization of Ar. The origin of these phenomenologies is explained and a prospectus for future work is presented.", author = "Soumyajit Saha and Jobin Jose and Deshmukh, \{Pranawa C.\} and G. Aravind and Dolmatov, \{Valeriy K.\} and Kheifets, \{Anatoli S.\} and Manson, \{Steven T.\}", note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.", year = "2019", month = apr, day = "8", doi = "10.1103/PhysRevA.99.043407", language = "English", volume = "99", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Attosecond angular streaking and tunnelling time in atomic hydrogen @article{9f3d4576ce4e4c32b999a4594c250f7e, title = "Attosecond angular streaking and tunnelling time in atomic hydrogen", abstract = "The tunnelling of a particle through a potential barrier is a key feature of quantum mechanics that goes to the core of wave–particle duality. The phenomenon has no counterpart in classical physics, and there are no well constructed dynamical observables that could be used to determine {\textquoteleft}tunnelling times{\textquoteright}. The resulting debate1–5 about whether a tunnelling quantum particle spends a finite and measurable time under a potential barrier was reignited in recent years by the advent of ultrafast lasers and attosecond metrology6. Particularly important is the attosecond angular streaking ({\textquoteleft}attoclock{\textquoteright}) technique7, which can time the release of electrons in strong-field ionization with a precision of a few attoseconds. Initial measurements7–10 confirmed the prevailing view that tunnelling is instantaneous, but later studies11,12 involving multi-electron atoms—which cannot be accurately modelled, complicating interpretation of the ionization dynamics—claimed evidence for finite tunnelling times. By contrast, the simplicity of the hydrogen atom enables precise experimental measurements and calculations13–15 and makes it a convenient benchmark. Here we report attoclock and momentum-space imaging16 experiments on atomic hydrogen and compare these results with accurate simulations based on the three-dimensional time-dependent Schr{\"o}dinger equation and our experimental laser pulse parameters. We find excellent agreement between measured and simulated data, confirming the conclusions of an earlier theoretical study17 of the attoclock technique in atomic hydrogen that presented a compelling argument for instantaneous tunnelling. In addition, we identify the Coulomb potential as the sole cause of the measured angle between the directions of electron emission and peak electric field: this angle had been attributed11,12 to finite tunnelling times. We put an upper limit of 1.8 attoseconds on any tunnelling delay, in agreement with recent theoretical findings18 and ruling out the interpretation of all commonly used {\textquoteleft}tunnelling times{\textquoteright}19 as {\textquoteleft}time spent by an electron under the potential barrier{\textquoteright}20.", author = "Sainadh, \{U. Satya\} and Han Xu and Xiaoshan Wang and A. Atia-Tul-Noor and Wallace, \{William C.\} and Nicolas Douguet and Alexander Bray and Igor Ivanov and Klaus Bartschat and Anatoli Kheifets and Sang, \{R. T.\} and Litvinyuk, \{I. V.\}", note = "Publisher Copyright: {\textcopyright} 2019, The Author(s), under exclusive licence to Springer Nature Limited.", year = "2019", month = apr, day = "4", doi = "10.1038/s41586-019-1028-3", language = "English", volume = "568", pages = "75--77", journal = "Nature", issn = "0028-0836", publisher = "Nature Research", number = "7750", } . Nature.

Strong dependence of photoionization time delay on energy and angle in the neighborhood of Fano resonances @article{8f83ae38b12c4e1296d9583841e4d619, title = "Strong dependence of photoionization time delay on energy and angle in the neighborhood of Fano resonances", abstract = "We uncover dramatic variations of the Wigner photoemission time delay with energy and angle in the vicinity of a Fano resonance with the time delay taking opposite signs at different angles at the same energy as well as at the opposite sides of the resonance at the same angle. These variations are illustrated by choosing the Ne 2s→3p autoionizing state as a case study. Moreover, we demonstrate the existence of strikingly significant changes in time delay due to relativistic effects despite Ne being a low-Z atom. This finding shows the possibility for utilizing time delay chronoscopy as a route towards experimental probing of relativistic interactions and the phases of individual transition matrix elements upon atomic photoionization of low-Z atoms. Finally, we develop a practical parametrization to model and explain the angle and energy variation of the autoionizing resonance time delay in the nonrelativistic limit.", author = "Sourav Banerjee and Deshmukh, \{Pranawa C.\} and Dolmatov, \{Valeriy K.\} and Manson, \{Steven T.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.", year = "2019", month = jan, day = "14", doi = "10.1103/PhysRevA.99.013416", language = "English", volume = "99", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Quan, Wei, Serov, Vladislav V., Wei, MingZheng, Zhao, Meng, Zhou, Yu, Wang, YanLan, Lai, XuanYang, Kheifets, Anatoli S., Liu, XiaoJun (2019). Attosecond Molecular Angular Streaking with All-Ionic Fragments Detection . Physical Review Letters.

Bray, Alexander W., Freeman, David, Eckart, Sebastian, Kheifets, Anatoli S. (2019). Correlation enhancement of high-order harmonic generation in Xe . Physical Review A.

Serov, Vladislav V., Bray, Alexander W., Kheifets, Anatoli S. (2019). Numerical attoclock on atomic and molecular hydrogen . Physical Review A.

Saha, Soumyajit, Deshmukh, Pranawa C., Kheifets, Anatoli S., Manson, Steven T. (2019). Dominance of correlation and relativistic effects on photodetachment time delay well above threshold . Physical Review A.

Saha, Soumyajit, Jose, Jobin, Deshmukh, I. Pranawa C., Aravind, G., Dolmatov, Valeriy K., Kheifets, Anatoli S., Manson, Steven T. (2019). Wigner time delay in photodetachment . Physical Review A.

Sainadh, U. Satya and Xu, Han and Wang, Xiaoshan and Atia-Tul-Noor, A. and Wallace, William C. and Douguet, Nicolas and Bray, Alexander and Ivanov, Igor and Bartschat, Klaus and Kheifets, Anatoli and Sang, R. T. and Litvinyuk, I. V.(2019). Attosecond angular streaking and tunnelling time in atomic hydrogen . Nature. 568. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 75--77.

Banerjee, Sourav and Deshmukh, Pranawa C. and Dolmatov, Valeriy K. and Manson, Steven T. and Kheifets, Anatoli S.(2019). Strong dependence of photoionization time delay on energy and angle in the neighborhood of Fano resonances . Phys. Rev. A. 99. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 013416. American Physical Society

Banerjee, Sourav, Deshmukh, Pranawa C., Dolmatov, Valeriy K., Manson, Steven T., Kheifets, Anatoli S. (2019). Strong dependence of photoionization time delay on energy and angle in the neighborhood of Fano resonances . Physical Review A.

Using a passively stable attosecond beamline for relative phjavascript:void(0);otoemission time delays at high XUV photon energies @article{8f80c4ee4c034c7e9d953b28c6912f55, title = "Using a passively stable attosecond beamline for relative phjavascript:void(0);otoemission time delays at high XUV photon energies", abstract = "We present and demonstrate an experimental scheme that enables overlap-free reconstruction of attosecond beating by the interference of two-photon transition (RABBITT) measurements at high extreme-ultraviolet (XUV) photon energies. A compact passively-stabilized attosecond beamline employing a multilayer (ML) mirror allows us to obtain XUV pulses consisting of only two odd high-harmonic orders from an attosecond pulse train (APT). We compare our new technique to existing schemes that are used to perform RABBITT measurements and discuss how our scheme resolves the limitations imposed by spectral complexity of the harmonic comb at high photon energies. We further demonstrate first applications of our scheme for rare gases and gas mixtures, and show that this scheme can be extended to gas-molecule mixtures.", author = "Arohi Jain and Thomas Gaumnitz and Anatoli Kheifets and W{\"o}rner, \{Hans Jakob\}", note = "Publisher Copyright: {\textcopyright} 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.", year = "2018", month = oct, day = "29", doi = "10.1364/OE.26.028604", language = "English", volume = "26", pages = "28604--28620", journal = "Optics Express", issn = "1094-4087", publisher = "Optica Publishing Group", number = "22", } . Optics Express.

Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization @article{4c7fcc9d63424e3eaff3771007e979f4, title = "Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization", abstract = "We report on a kinematically complete measurement of double ionization of helium by a single 1100 eV circularly polarized photon. By exploiting dipole selection rules in the two-electron continuum state, we observed the angular emission pattern of electrons originating from a pure quadrupole transition. Our fully differential experimental data and companion ab initio nonperturbative theory show the separation of dipole and quadrupole contributions to photo-double-ionization and provide new insight into the nature of the quasifree mechanism.", author = "S. Grundmann and F. Trinter and Bray, \{A. W.\} and S. Eckart and J. Rist and G. Kastirke and D. Metz and S. Klumpp and J. Viefhaus and Schmidt, \{L. Ph H.\} and Williams, \{J. B.\} and R. D{\"o}rner and T. Jahnke and Sch{\"o}ffler, \{M. S.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2018 American Physical Society.", year = "2018", month = oct, day = "23", doi = "10.1103/PhysRevLett.121.173003", language = "English", volume = "121", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "17", } . Physical Review Letters.

Photoionization of Xe and Xe@ C60 from the 4d shell in RABBITT fields @article{6d52fe3565d14b609d5ab80bbd062b55, title = "Photoionization of Xe and Xe@ C60 from the 4d shell in RABBITT fields", abstract = "We consider photoemission from the 4d shell of the free Xe and encapsulated Xe@C60 atoms by ionizing XUV and probing IR fields typical for a RABBITT (reconstruction of attosecond beating by interference of two-photon transitions) measurement. Our theoretical model is based on the numerical solution of the time-dependent Schr{\"o}dinger equation in the single-active-electron approximation. The fullerene C60 cage is represented by a finite-width well potential. We test our model against an analogous set of nonrelativistic [Phys. Rev. A 89, 053424 (2014)PLRAAN1050-294710.1103/PhysRevA.89.053424] and relativistic [Phys. Rev. A 96, 053407 (2017)2469-992610.1103/PhysRevA.96.053407] calculations for the 4d shell of Xe and Xe@C60 driven by a continuous XUV field. Based on this verification, we make predictions for the total ionization probability, angular anisotropy β parameter, and the angular-dependent atomic time delay τa from the threshold to several hundred eV of excess energy.", author = "Bray, \{Alexander W.\} and Faiza Naseem and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2018 American Physical Society.", year = "2018", month = oct, day = "18", doi = "10.1103/PhysRevA.98.043427", language = "English", volume = "98", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Keldysh-Rutherford Model for the Attoclock @article{a0c2492e35a34fa081ccb940c2865938, title = "Keldysh-Rutherford Model for the Attoclock", abstract = "We demonstrate a clear similarity between attoclock offset angles and Rutherford scattering angles taking the Keldysh tunneling width as the impact parameter and the vector potential of the driving pulse as the asymptotic velocity. This simple model is tested against the solution of the time-dependent Schr{\"o}dinger equation using hydrogenic and screened (Yukawa) potentials of equal binding energy. We observe a smooth transition from a hydrogenic to {"}hard-zero{"} intensity dependence of the offset angle with variation of the Yukawa screening parameter. Additionally, we make a comparison with the attoclock offset angles for various noble gases obtained with the classical-trajectory Monte Carlo method. In all cases we find a close correspondence between the model predictions and numerical calculations. This suggests a largely Coulombic origin of the attoclock offset angle and casts further doubt on its interpretation in terms of a finite tunneling time.", author = "Bray, \{Alexander W.\} and Sebastian Eckart and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2018 American Physical Society.", year = "2018", month = sep, day = "20", doi = "10.1103/PhysRevLett.121.123201", language = "English", volume = "121", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "12", } . Physical Review Letters.

Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry @article{338b65e4cc93425183c652f5e33283ec, title = "Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry", abstract = "Attosecond photoemission delays for all the valence (5p3∕2, 5p1∕2, 5s, 4d5∕2, 4d3∕2) subshells of xenon have been accessed using the interferometric RABBITT technique. The 4d subshell delays in Xe have been accessed for the first time, to the best of our knowledge, due to the high photon energy used. A novel technique of single-shot referencing in the collinear back-focusing geometry has been introduced. This enables us to distinguish the signal from principal photoelectron peaks due to ionization by extreme ultraviolet radiation only and infrared-induced sideband contributions, especially in the regions of spectral overlap.", author = "Arohi Jain and Thomas Gaumnitz and Alexander Bray and Anatoli Kheifets and W{\"o}rner, \{Hans Jakob\}", note = "Publisher Copyright: {\textcopyright} 2018 Optical Society of America.", year = "2018", month = sep, day = "15", doi = "10.1364/OL.43.004510", language = "English", volume = "43", pages = "4510--4513", journal = "Optics Letters", issn = "0146-9592", publisher = "Optica Publishing Group", number = "18", } . Optics Letters.

Intershell-correlation-induced time delay in atomic photoionization @article{d29547ab06174cc29b64d4be7e383d8b, title = "Intershell-correlation-induced time delay in atomic photoionization", abstract = "We predict an observable Wigner time delay in outer atomic shell photoionization near inner shell thresholds. The near-threshold increase of time delay is caused by intershell correlation and serves as a sensitive probe of this effect. The time delay increase is present even when the inner and outer shell thresholds are hundreds of electron volts apart. We illustrate this observation by several prototypical examples in noble gas atoms from Ne to Kr. In our study, we employ the random phase approximation with exchange and its relativistic generalization. We also support our findings by a simplified, yet quite insightful, treatment within the lowest-order perturbation theory.", author = "Keating, \{D. A.\} and Manson, \{S. T.\} and Dolmatov, \{V. K.\} and A. Mandal and Deshmukh, \{P. C.\} and Faiza Naseem and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2018 American Physical Society.", year = "2018", month = jul, day = "24", doi = "10.1103/PhysRevA.98.013420", language = "English", volume = "98", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Orientation-dependent stereo Wigner time delay and electron localization in a small molecule @article{dfb91738ecf94cda8b8747cb3387e73f, title = "Orientation-dependent stereo Wigner time delay and electron localization in a small molecule", abstract = "Attosecond metrology of atoms has accessed the time scale of the most fundamental processes in quantum mechanics. Transferring the time-resolved photoelectric effect from atoms to molecules considerably increases experimental and theoretical challenges. Here we show that orientation- and energy-resolved measurements characterize the molecular stereo Wigner time delay. This observable provides direct information on the localization of the excited electron wave packet within the molecular potential. Furthermore, we demonstrate that photoelectrons resulting from the dissociative ionization process of the CO molecule are preferentially emitted from the carbon end for dissociative 2S states and from the center and oxygen end for the 2P states of the molecular ion. Supported by comprehensive theoretical calculations, this work constitutes a complete spatially and temporally resolved reconstruction of the molecular photoelectric effect.", author = "J. Vos and L. Cattaneo and S. Patchkovskii and T. Zimmermann and C. Cirelli and M. Lucchini and A. Kheifets and Landsman, \{A. S.\} and U. Keller", note = "Publisher Copyright: {\textcopyright} 2017 The Authors.", year = "2018", month = jun, day = "22", doi = "10.1126/science.aao4731", language = "English", volume = "360", pages = "1326--1330", journal = "Science", issn = "0036-8075", publisher = "American Association for the Advancement of Science", number = "6395", } . Science.

Simulation of angular-resolved RABBITT measurements in noble-gas atoms @article{670aa5f018cc4b5caabfa1e5548c8481, title = "Simulation of angular-resolved RABBITT measurements in noble-gas atoms", abstract = "We simulate angular-resolved RABBITT (reconstruction of attosecond beating by interference of two-photon transitions) measurements on valence shells of noble-gas atoms (Ne, Ar, Kr, and Xe). Our nonperturbative numerical simulation is based on solution of the time-dependent Schr{\"o}dinger equation (TDSE) for a target atom driven by an ionizing XUV and dressing IR fields. From these simulations we extract the angular-dependent magnitude and phase of the RABBITT oscillations and deduce the corresponding angular anisotropy β parameter and Wigner time delay τW for the single XUV photon absorption that initiates the RABBITT process. Said β and τW parameters are compared with calculations in the random-phase approximation with exchange (RPAE), which includes intershell correlation. This comparison is used to test various effective potentials employed in the one-electron TDSE. In lighter atoms (Ne and Ar), several effective potentials are found to provide accurate simulations of RABBITT measurements for a wide range of photon energies up to 100 eV above the valence-shell threshold. In heavier atoms (Kr and Xe), the onset of strong correlation with the d shell restricts the validity of the single active electron approximation to several tens of eV above the valence-shell threshold.", author = "Bray, \{Alexander W.\} and Faiza Naseem and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2018 American Physical Society.", year = "2018", month = jun, day = "8", doi = "10.1103/PhysRevA.97.063404", language = "English", volume = "97", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Subcycle interference upon tunnel ionization by counter-rotating two-color fields @article{7e5c947163ed434d875b9da25b972a6a, title = "Subcycle interference upon tunnel ionization by counter-rotating two-color fields", abstract = "We report on three-dimensional (3D) electron momentum distributions from single ionization of helium by a laser pulse consisting of two counter-rotating circularly polarized fields (390 and 780 nm). A pronounced 3D low-energy structure and subcycle interferences are observed experimentally and reproduced numerically using a trajectory-based semiclassical simulation. The orientation of the low-energy structure in the polarization plane is verified by numerical simulations solving the time-dependent Schr{\"o}dinger equation.", author = "S. Eckart and M. Kunitski and I. Ivanov and M. Richter and K. Fehre and A. Hartung and J. Rist and K. Henrichs and D. Trabert and N. Schlott and Schmidt, \{L. Ph H.\} and T. Jahnke and Sch{\"o}ffler, \{M. S.\} and A. Kheifets and R. D{\"o}rner", note = "Publisher Copyright: {\textcopyright} 2018 American Physical Society.", year = "2018", month = apr, day = "13", doi = "10.1103/PhysRevA.97.041402", language = "English", volume = "97", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Wigner-Eisenbud-Smith photoionization time delay due to autoioinization resonances @article{f22bbe930b464b2e8d355ad750e98a27, title = "Wigner-Eisenbud-Smith photoionization time delay due to autoioinization resonances", abstract = "An empirical ansatz for the complex photoionization amplitude and Wigner-Eisenbud-Smith time delay in the vicinity of a Fano autoionization resonance are proposed to evaluate and interpret the time delay in the resonant region. The utility of this expression is evaluated in comparison with accurate numerical calculations employing the ab initio relativistic random phase approximation and relativistic multichannel quantum defect theory. The indisputably good qualitative agreement (and semiquantitative agreement) between corresponding results of the proposed model and results produced by the ab initio theories proves the usability of the model. In addition, the phenomenology of the time delay in the vicinity of multichannel autoionizing resonances is detailed.", keywords = "Fano parametrisation, Wigner-Eisenbud-Smith time delay, autoionization, relativistic multichannel quantum defect theory, relativistic random phase approximation", author = "Deshmukh, \{P. C.\} and A. Kumar and Varma, \{H. R.\} and S. Banerjee and Manson, \{Steven T.\} and Dolmatov, \{V. K.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2018 IOP Publishing Ltd.", year = "2018", month = mar, day = "5", doi = "10.1088/1361-6455/aaae33", language = "English", volume = "51", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "6", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Waitz, M., Bello, R. Y., Metz, D., Lower, J., Trinter, F., Schober, C., Keiling, M., Lenz, U., Pitzer, M., Mertens, K., et al.(2018). Imaging the square of the correlated two-electron wave function of a hydrogen molecule (vol 8, 2018) . Nature Communications. 9.

Kheifets, Anatoli, Jain, Arohi, Gaumnitz, Thomas, Woerner, Hans Jakob(2018). Using a passively stable attosecond beamline for relative phjavascript:void(0);otoemission time delays at high XUV photon energies . Optics Express. 26. (22). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 28604-28620.

Anatoli Kheifets, Arohi Jain, Thomas Gaumnitz, Hans Jakob W&#246;rner (2018). Using a passively stable attosecond beamline for relative phjavascript:void(0);otoemission time delays at high XUV photon energies . Optics Express.

Grundmann, S., Trinter, F., Bray, A. W., Eckart, S., Rist, J., Kastirke, G., Metz, D., Klumpp, S., Viefhaus, J., Schmidt, L. Ph. H., et al.(2018). Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization . Physical Review Letters. 121. (17).

Grundmann, S., Trinter, F., Bray, A. W., Eckart, S., Rist, J., Kastirke, G., Metz, D., Klumpp, S., Viefhaus, J., Schmidt, L. Ph. H., et al. (2018). Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization . Physical Review Letters.

Bray, Alexander W., Naseem, Faiza, Kheifets, Anatoli S., Bray, Alexander W., Naseem, Faiza, Kheifets, Anatoli S.(2018). Photoionization of Xe and Xe@C-60 from the 4d shell in RABBITT fields . Physical Review a. 98. (4).

Bray, Alexander W., Eckart, Sebastian, Kheifets, Anatoli S.(2018). Keldysh-Rutherford Model for the Attoclock . Physical Review Letters. 121. (12).

Bray, Alexander W., Eckart, Sebastian, Kheifets, Anatoli S. (2018). Keldysh-Rutherford Model for the Attoclock . Physical Review Letters.

Kheifets, Anatoli, Jain, Arohi, Gaumnitz, Thomas, Bray, Alexander, Woerner, Hans Jakob(2018). Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry . Optics Letters. 43. (18). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4510-4513.

Deshmukh, P. C., Kumar, A., Varma, H. R., Banerjee, S., Manson, Steven T., Dolmatov, V. K., Kheifets, A. S.(2018). Wigner-Eisenbud-Smith photoionization time delay due to autoioinization resonances . Journal of Physics B-Atomic Molecular and Optical Physics. 51. (6).

Bray, Alexander W., Naseem, Faiza, Kheifets, Anatoli S.(2018). Simulation of angular-resolved RABBITT measurements in noble-gas atoms . Physical Review a. 97. (6).

Bray, Alexander W., Naseem, Faiza, Kheifets, Anatoli S. (2018). Simulation of angular-resolved RABBITT measurements in noble-gas atoms . Physical Review A.

Deshmukh, P. C., Kumar, A., Varma, H. R., Banerjee, S., Manson, Steven T., Dolmatov, V. K., Kheifets, A. S. (2018). Wigner-Eisenbud-Smith photoionization time delay due to autoioinization resonances . Journal of Physics B: Atomic, Molecular and Optical Physics.

Keating, D. A., Manson, S. T., Dolmatov, V. K., Mandal, A., Deshmukh, P. C., Naseem, Faiza, Kheifets, A. S.(2018). Intershell-correlation-induced time delay in atomic photoionization . Physical Review a. 98. (1).

Keating, D. A., Manson, S. T., Dolmatov, V. K., Mandal, A., Deshmukh, P. C., Naseem, Faiza, Kheifets, A. S. (2018). Intershell-correlation-induced time delay in atomic photoionization . Physical Review A.

Vos, J., Cattaneo, L., Patchkovskii, S., Zimmermann, T., Cirelli, C., Lucchini, M., Kheifets, A., Landsman, A. S., Keller, U. (2018). Orientation-dependent stereo Wigner time delay and electron localization in a small molecule . Science.

Bray, Alexander W., Naseem, Faiza, Kheifets, Anatoli S. (2018). Photoionization of Xe and Xe@C-60 from the 4d shell in RABBITT fields . Physical Review A.

Kheifets, Anatoli, Jain, Arohi, Gaumnitz, Thomas, Bray, Alexander, Woerner, Hans Jakob (2018). Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry . Optics Letters.

Vos, J., Cattaneo, L., Patchkovskii, S., Zimmermann, T., Cirelli, C., Lucchini, M., Kheifets, A., Landsman, A. S., Keller, U.(2018). Orientation-dependent stereo Wigner time delay and electron localization in a small molecule . Science. 360. (6395). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1326-1330.

Eckart, S., Kunitski, M., Ivanov, I., Richter, M., Fehre, K., Hartung, A., Rist, J., Henrichs, K., Trabert, D., Schlott, N., et al.(2018). Subcycle interference upon tunnel ionization by counter-rotating two-color fields . Physical Review a. 97. (4).

Eckart, S., Kunitski, M., Ivanov, I., Richter, M., Fehre, K., Hartung, A., Rist, J., Henrichs, K., Trabert, D., Schlott, N., et al. (2018). Subcycle interference upon tunnel ionization by counter-rotating two-color fields . Physical Review A.

Imaging the square of the correlated two-electron wave function of a hydrogen molecule @article{c440f2e61fcb4294995c62d0d4ec47bb, title = "Imaging the square of the correlated two-electron wave function of a hydrogen molecule", abstract = "The toolbox for imaging molecules is well-equipped today. Some techniques visualize the geometrical structure, others the electron density or electron orbitals. Molecules are many-body systems for which the correlation between the constituents is decisive and the spatial and the momentum distribution of one electron depends on those of the other electrons and the nuclei. Such correlations have escaped direct observation by imaging techniques so far. Here, we implement an imaging scheme which visualizes correlations between electrons by coincident detection of the reaction fragments after high energy photofragmentation. With this technique, we examine the H2 two-electron wave function in which electron-electron correlation beyond the mean-field level is prominent. We visualize the dependence of the wave function on the internuclear distance. High energy photoelectrons are shown to be a powerful tool for molecular imaging. Our study paves the way for future time resolved correlation imaging at FELs and laser based X-ray sources.", author = "M. Waitz and Bello, \{R. Y.\} and D. Metz and J. Lower and F. Trinter and C. Schober and M. Keiling and U. Lenz and M. Pitzer and K. Mertens and M. Martins and J. Viefhaus and S. Klumpp and T. Weber and Schmidt, \{L. Ph H.\} and Williams, \{J. B.\} and Sch{\"o}ffler, \{M. S.\} and Serov, \{V. V.\} and Kheifets, \{A. S.\} and L. Argenti and A. Palacios and F. Mart{\'i}n and T. Jahnke and R. D{\"o}rner", note = "Publisher Copyright: {\textcopyright} 2017 The Author(s).", year = "2017", month = dec, day = "1", doi = "10.1038/s41467-017-02437-9", language = "English", volume = "8", journal = "Nature Communications", issn = "2041-1723", publisher = "Nature Research", number = "1", } . Nature Communications.

Time delay in XUV/IR photoionization of H2O @article{c41fcdaf65fd4f93bbe07b21b6a70e39, title = "Time delay in XUV/IR photoionization of H2O", abstract = "We solve the time-dependent Schr{\"o}dinger equation describing a water molecule driven by a superposition of the extreme ultraviolet and IR pulses typical for a reconstruction of attosecond beating by interference of two-photon transitions experiment. This solution is obtained by a combination of the time-dependent coordinate scaling and the density functional theory with self-interaction correction. Results of this solution are used to determine the time delay in photoionization of the water and hydrogen molecules.", author = "Serov, \{Vladislav V.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} 2017 Author(s).", year = "2017", month = nov, day = "28", doi = "10.1063/1.4993493", language = "English", volume = "147", journal = "Journal of Chemical Physics", issn = "0021-9606", publisher = "American Institute of Physics", number = "20", } . Journal of Chemical Physics.

Angle-resolved Wigner time delay in atomic photoionization @article{d1f35c8537734d02afa5a6e3b179dc3e, title = "Angle-resolved Wigner time delay in atomic photoionization: The 4d subshell of free and confined Xe", abstract = "The angular dependence of photoemission time delay for the inner nd3/2 and nd5/2 subshells of free and confined Xe is studied in the dipole relativistic random phase approximation. A finite spherical annular well potential is used to model the confinement due to fullerene C60 cage. Near cancellations in a variety of the dipole amplitudes, Cooper-like minima, are found. The effects of confinement on the angular dependence, primarily confinement resonances, are demonstrated and detailed.", author = "A. Mandal and Deshmukh, \{P. C.\} and Kheifets, \{A. S.\} and Dolmatov, \{V. K.\} and Manson, \{S. T.\}", note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.", year = "2017", month = nov, day = "9", doi = "10.1103/PhysRevA.96.053407", language = "English", volume = "96", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "5", } . Physical Review A.

Attosecond streaking in the water window @article{fd66978621e84e60a5c1dbe79cbf63dc, title = "Attosecond streaking in the water window: A new regime of attosecond pulse characterization", abstract = "We report on the first streaking measurement of water-window attosecond pulses generated via highharmonic generation, driven by sub-2-cycle, carrier-to-envelope-phase-stable, 1850-nm laser pulses. Both the central photon energy and the energy bandwidth far exceed what has been demonstrated thus far, warranting the investigation of the attosecond streaking technique for the soft-x-ray regime and the limits of the FROGCRAB retrieval algorithm under such conditions. We also discuss the problem of attochirp compensation and issues regarding much lower photoionization cross sections compared with the extreme ultraviolet in addition to the fact that several shells of target gases are accessed simultaneously. Based on our investigation, we caution that the vastly different conditions in the soft-x-ray regime warrant a diligent examination of the fidelity of the measurement and the retrieval procedure.", author = "Cousin, \{Seth L.\} and \{Di Palo\}, Nicola and B{\'a}rbara Buades and Teichmann, \{Stephan M.\} and M. Reduzzi and M. Devetta and A. Kheifets and G. Sansone and Jens Biegert", year = "2017", month = nov, day = "2", doi = "10.1103/PhysRevX.7.041030", language = "English", volume = "7", journal = "Physical Review X", issn = "2160-3308", publisher = "American Physical Society", number = "4", } . Physical Review X.

Photoionization Time delay in atomic Barium @article{78e5862cc65447428fc65a35572b9c2f, title = "Photoionization Time delay in atomic Barium", abstract = "Synopsis Wigner-Eisenbud-Smith (WES) photoionization time delay is calculated for atomic barium 5s subshell using Relativistic Random Phase Approximation (RRPA), RRPA with relaxation (RRPA-R) and the Relativistic Multi-Configuration Tamm-Dancoff (RMCTD) techniques. Electron correlations are treated differently in different many body methods; the WES time delay is sensitive to these differences. The present study is aimed at determining the suitability of various many-body methods for the study of the WES time-delay.", author = "Aarthi Ganesan and Deshmukh, \{Pranawa C.\} and Kheifets, \{Anatoli S.\} and Dolmatov, \{Valeriy K.\} and Manson, \{Steven T.\}", year = "2017", month = aug, day = "18", doi = "10.1088/1742-6596/875/3/022021", language = "English", volume = "875", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "3", note = "30th International Conference on Photonic, Electronic, and Atomic Collisions, ICPEAC 2017 ; Conference date: 26-07-2017 Through 01-08-2017", } . Journal of Physics: Conference Series.

Confinement effects and angular dependence of Wigner-Eisenbud-Smith time delay @article{6735b39a5ba8462caf2f23046b6311e4, title = "Confinement effects and angular dependence of Wigner-Eisenbud-Smith time delay", abstract = "Synopsis The effect of confinement on the angle dependent Wigner-Eisenbud-Smith time delay in photoionization of atomic xenon is studied. A finite spherical annular well potential is used to model the nearly spherical confinement due to fullerene C60 molecular cage. The confinement is seen to have a significant effect on the time delay.", author = "A. Mandal and Deshmukh, \{P. C.\} and Dolmatov, \{V. K.\} and A. Kheifets and Manson, \{S. T.\}", year = "2017", month = aug, day = "18", doi = "10.1088/1742-6596/875/3/022022", language = "English", volume = "875", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "3", note = "30th International Conference on Photonic, Electronic, and Atomic Collisions, ICPEAC 2017 ; Conference date: 26-07-2017 Through 01-08-2017", } . Journal of Physics: Conference Series.

Attoclock using Atomic Hydrogen @article{fb1e0b3613294e2cba6477e3fc5219a0, title = "Attoclock using Atomic Hydrogen", abstract = "Synopsis We present the results of attosecond angular streaking of atomic Hydrogen using elliptically polarized, 5.5 fs pulses that are centered around 770 nm, within the intensity range of 1.65 to 4 X 1014 W/cm2. We measure angular offsets in the photo-electron momentum distribution relative to the peak of the electric field of light in the polarization plane .We find a strong agreement in these results with the solutions of complete 3D-TDSE simulations. Further, we compute the contribution of coulomb effects (between the ionized electron-parent ion) to the measured angular offsets using Yukawa potential, subtracting which yields the real tunneling delays .", author = "\{Satya Sainadh\}, U. and Han Xu and X. Wang and Atia-Tul-Noor and Wallace, \{William C.\} and N. Douguet and Igor Ivanov and Klaus Bartschat and Anatoli Kheifets and Sang, \{R. T.\} and Igor Litvinyuk", year = "2017", month = aug, day = "18", doi = "10.1088/1742-6596/875/3/022039", language = "English", volume = "875", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "3", note = "30th International Conference on Photonic, Electronic, and Atomic Collisions, ICPEAC 2017 ; Conference date: 26-07-2017 Through 01-08-2017", } . Journal of Physics: Conference Series.

Study of angular dependence of photoionization time delay in (n-1)d → ϵ f channels for Zn, Cd and Hg @article{a6054f28f40f4656b23f138aacdbe64b, title = "Study of angular dependence of photoionization time delay in (n-1)d → ϵ f channels for Zn, Cd and Hg", abstract = "Synopsis The angular dependence of Wigner-Eisenbud-Smith photoionization time delay has been investigated for the nd ! e f dipole channels in atomic Zn, Cd and Hg using the relativistic random phase approximation (RRPA). The studies have been carried out also in the nonrelativistic limit. This technique enables identification of the relativistic effects on the angular dependence of photoionization time delay.", author = "S. Banerjee and Deshmukh, \{P. C.\} and A. Kheifets and Dolmatov, \{V. K.\} and Manson, \{S. T.\}", year = "2017", month = aug, day = "18", doi = "10.1088/1742-6596/875/3/022025", language = "English", volume = "875", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "3", note = "30th International Conference on Photonic, Electronic, and Atomic Collisions, ICPEAC 2017 ; Conference date: 26-07-2017 Through 01-08-2017", } . Journal of Physics: Conference Series.

Observation and Control of Laser-Enabled Auger Decay @article{f50c43e557414fcdb4e7f6b8122005f6, title = "Observation and Control of Laser-Enabled Auger Decay", abstract = "Single-photon laser-enabled Auger decay (spLEAD) is predicted theoretically [B. Cooper and V. Averbukh, Phys. Rev. Lett. 111, 083004 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.083004] and here we report its first experimental observation in neon. Using coherent, bichromatic free-electron laser pulses, we detect the process and coherently control the angular distribution of the emitted electrons by varying the phase difference between the two laser fields. Since spLEAD is highly sensitive to electron correlation, this is a promising method for probing both correlation and ultrafast hole migration in more complex systems.", author = "D. Iablonskyi and K. Ueda and Ishikawa, \{K. L.\} and Kheifets, \{A. S.\} and P. Carpeggiani and M. Reduzzi and H. Ahmadi and A. Comby and G. Sansone and T. Csizmadia and S. Kuehn and E. Ovcharenko and T. Mazza and M. Meyer and A. Fischer and C. Callegari and O. Plekan and P. Finetti and E. Allaria and E. Ferrari and E. Roussel and D. Gauthier and L. Giannessi and Prince, \{K. C.\}", note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.", year = "2017", month = aug, day = "14", doi = "10.1103/PhysRevLett.119.073203", language = "English", volume = "119", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "7", } . Physical Review Letters.

Angle-dependent time delay in two-color XUV+IR photoemission of He and Ne @article{6d38ef45cc834fffb7e45a95e16a77cb, title = "Angle-dependent time delay in two-color XUV+IR photoemission of He and Ne", abstract = "We solve the time-dependent Schr{\"o}dinger equation for a noble gas atom (He and Ne) driven by an ionizing XUV and dressing IR fields. From this solution we deduce an angular dependence of the photoemission time delay as measured by the RABBITT (reconstruction of attosecond beating by interference of two-photon transitions) technique. We use a recent angle-resolved RABBITT measurement on helium [S. Heuser et al., Phys. Rev. A 94, 063409 (2016)2469-992610.1103/PhysRevA.94.063409] to test and calibrate our theoretical model. Based on this calibration, we find no significant difference between the time delay in He measured in the angle-integrated RABBITT experiments [C. Palatchi et al., J. Phys. B 47, 245003 (2014)JPAPEH0953-407510.1088/0953-4075/47/24/245003 and D. Gu{\'e}not, J. Phys. B 47, 245602 (2014)JPAPEH0953-407510.1088/0953-4075/47/24/245602] and measured or calculated in the polarization axis direction. The angular dependence of the photoemission time delay of Ne is shown to be qualitatively different from He because of the different orbital character of the valence 2p orbital. The angular momentum projection dependence of the time delay in Ne is also investigated.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.", year = "2017", month = jul, day = "11", doi = "10.1103/PhysRevA.96.013408", language = "English", volume = "96", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Measuring laser carrier-envelope-phase effects in the noble gases with an atomic hydrogen calibration standard @article{f281095629d5498296302131cf524ef9, title = "Measuring laser carrier-envelope-phase effects in the noble gases with an atomic hydrogen calibration standard", abstract = "We present accurate measurements of carrier-envelope-phase effects on ionization of the noble gases with few-cycle laser pulses. The experimental apparatus is calibrated by using atomic hydrogen data to remove any systematic offsets and thereby obtain accurate CEP data on other generally used noble gases such as Ar, Kr, and Xe. Experimental results for H are well supported by exact time-dependent Schr{\"o}dinger equation theoretical simulations; however, significant differences are observed in the case of the noble gases.", author = "Champak Khurmi and Wallace, \{W. C.\} and Sainadh, \{Satya U.\} and Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Tong, \{X. M.\} and Litvinyuk, \{I. V.\} and Sang, \{R. T.\} and D. Kielpinski", note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.", year = "2017", month = jul, day = "7", doi = "10.1103/PhysRevA.96.013404", language = "English", volume = "96", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Calculation of atomic photoionization using the nonsingular convergent close-coupling method @article{45d56682177048598a3480fdd979fb63, title = "Calculation of atomic photoionization using the nonsingular convergent close-coupling method", abstract = "The convergent close-coupling method for atomic photoionization is modified by treating the singularity in the Green's function analytically. The resultant close-coupling equations are then free of any singularities, and can be solved at all incident energies including at the exact thresholds. The utility and superiority of the approach is demonstrated by considering single photoionization of the ground state of helium at photoelectron energies from the ionic n=1,2,3 thresholds through to 1 keV. For completeness, the double photoionization cross section is also presented.", author = "Bray, \{A. W.\} and Kheifets, \{A. S.\} and I. Bray", note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.", year = "2017", month = may, day = "12", doi = "10.1103/PhysRevA.95.053405", language = "English", volume = "95", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "5", } . Physical Review A.

Spin-orbit delays in photoemission @article{5c834cf0e7064999a7e499d8f3792bfe, title = "Spin-orbit delays in photoemission", abstract = "Attosecond delays between photoelectron wave packets emitted from different electronic shells are now well established. Is there any delay between electrons originating from the same electronic shell but leaving the cation in different fine-structure states? This question is relevant for all attosecond photoemission studies involving heavy elements, be it atoms, molecules or solids. We answer this fundamental question by measuring energy-dependent delays between photoelectron wave packets associated with the P3/22 and P1/22 components of the electronic ground states of Xe+ and Kr+. We observe delays reaching up to 33±6 as in the case of Xe. Our results are compared with two state-of-the-art theories. Whereas both theories quantitatively agree with the results obtained for Kr, neither of them fully reproduces the experimental results in Xe. Performing delay measurements very close to the ionization thresholds, we compare the agreement of several analytical formulas for the continuum-continuum delays with experimental data. Our results show an important influence of spin-orbit coupling on attosecond photoionization delays, highlight the requirement for additional theory development, and offer a precision benchmark for such work.", author = "I. Jordan and M. Huppert and S. Pabst and Kheifets, \{A. S.\} and D. Baykusheva and W{\"o}rner, \{H. J.\}", note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.", year = "2017", month = jan, day = "10", doi = "10.1103/PhysRevA.95.013404", language = "English", volume = "95", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Ivanov, I. A., Kheifets, A. S.(2017). Angle-dependent time delay in two-color XUV plus IR photoemission of He and Ne . Physical Review a. 96. (1).

Waitz, M., Bello, R. Y., Metz, D., Lower, J., Trinter, F., Schober, C., Keiling, M., Lenz, U., Pitzer, M., Mertens, K., et al. (2017). Imaging the square of the correlated two-electron wave function of a hydrogen molecule . Nature Communications.

I. A. Ivanov, A. S. Kheifets (2017). Angle-dependent time delay in two-color XUV plus IR photoemission of He and Ne . Physical Review A.

Cousin, Seth L., Di Palo, Nicola, Buades, Barbara, Teichmann, Stephan M., Reduzzi, M., Devetta, M., Kheifets, A., Sansone, G., Biegert, Jens(2017). Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization . Physical Review X. 7. (4).

Mandal, A., Deshmukh, P. C., Kheifets, A. S., Dolmatov, V. K., Manson, S. T. (2017). Angle-resolvedWigner time delay in atomic photoionization: The 4d subshell of free and confined Xe . Physical Review A.

Khurmi, Champak, Wallace, W. C., Sainadh, Satya U., Ivanov, I. A., Kheifets, A. S., Tong, X. M., Litvinyuk, I. V., Sang, R. T., Kielpinski, D.(2017). Measuring laser carrier-envelope-phase effects in the noble gases with an atomic hydrogen calibration standard . Physical Review a. 96. (1).

Iablonskyi, D., Ueda, K., Ishikawa, K. L., Kheifets, A. S., Carpeggiani, P., Reduzzi, M., Ahmadi, H., Comby, A., Sansone, G., Csizmadia, T., et al.(2017). Observation and Control of Laser-Enabled Auger Decay . Physical Review Letters. 119. (7).

Khurmi, Champak, Wallace, W. C., Sainadh, Satya U., Ivanov, I. A., Kheifets, A. S., Tong, X. M., Litvinyuk, I. V., Sang, R. T., Kielpinski, D. (2017). Measuring laser carrier-envelope-phase effects in the noble gases with an atomic hydrogen calibration standard . Physical Review A.

Iablonskyi, D., Ueda, K., Ishikawa, K. L., Kheifets, A. S., Carpeggiani, P., Reduzzi, M., Ahmadi, H., Comby, A., Sansone, G., Csizmadia, T., et al. (2017). Observation and Control of Laser-Enabled Auger Decay . Physical Review Letters.

Jordan, I., Huppert, M., Pabst, S., Kheifets, A. S., Baykusheva, D., Worner, H. J.(2017). Spin-orbit delays in photoemission . Physical Review a. 95. (1).

Bray, A. W., Kheifets, A. S., Bray, I. (2017). Calculation of atomic photoionization using the nonsingular convergent close-coupling method . Physical Review A.

Jordan, I., Huppert, M., Pabst, S., Kheifets, A. S., Baykusheva, D., Worner, H. J., Jordan, I., Huppert, M., Pabst, S., Kheifets, A. S., et al. (2017). Spin-orbit delays in photoemission . Physical Review A.

Bray, A. W., Kheifets, A. S., Bray, I.(2017). Calculation of atomic photoionization using the nonsingular convergent close-coupling method . Physical Review a. 95. (5).

Serov, Vladislav V., Kheifets, Anatoli S.(2017). Time delay in XUV/IR photoionization of H2O . Journal of Chemical Physics. 147. (20).

Vladislav V. Serov, Anatoli S. Kheifets (2017). Time delay in XUV/IR photoionization of H2O . The Journal of Chemical Physics.

Mandal, A., Deshmukh, P. C., Kheifets, A. S., Dolmatov, V. K., Manson, S. T.(2017). Angle-resolvedWigner time delay in atomic photoionization: The 4d subshell of free and confined Xe . Physical Review a. 96. (5).

Cousin, Seth L., Di Palo, Nicola, Buades, Barbara, Teichmann, Stephan M., Reduzzi, M., Devetta, M., Kheifets, A., Sansone, G., Biegert, Jens (2017). Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization . Physical Review X.

Angular dependence of photoemission time delay in helium @article{da366df5b0174d908f59dd981ce00b79, title = "Angular dependence of photoemission time delay in helium", abstract = "Time delays of electrons emitted from an isotropic initial state with the absorption of a single photon and leaving behind an isotropic ion are angle independent. Using an interferometric method involving XUV attosecond pulse trains and an IR-probe field in combination with a detection scheme, which allows for full three-dimensional momentum resolution, we show that measured time delays between electrons liberated from the 1s2 spherically symmetric ground state of helium depend on the emission direction of the electrons relative to the common linear polarization axis of the ionizing XUV light and the IR-probing field. Such time delay anisotropy, for which we measure values as large as 60 as, is caused by the interplay between final quantum states with different symmetry and arises naturally whenever the photoionization process involves the exchange of more than one photon. With the support of accurate theoretical models, the angular dependence of the time delay is attributed to small phase differences that are induced in the laser-driven continuum transitions to the final states. Since most measurement techniques tracing attosecond electron dynamics involve the exchange of at least two photons, this is a general and significant effect that must be taken into account in all measurements of time delays involving photoionization processes.", author = "Sebastian Heuser and Gal{\'a}n, \{{\'A}lvaro Jim{\'e}nez\} and Claudio Cirelli and Carlos Marante and Mazyar Sabbar and Robert Boge and Matteo Lucchini and Lukas Gallmann and Igor Ivanov and Kheifets, \{Anatoli S.\} and Dahlstr{\"o}m, \{J. Marcus\} and Eva Lindroth and Luca Argenti and Fernando Mart{\'i}n and Ursula Keller", note = "Publisher Copyright: {\textcopyright} 2016 American Physical Society.", year = "2016", month = dec, day = "9", doi = "10.1103/PhysRevA.94.063409", language = "English", volume = "94", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Wigner photoemission time delay from endohedral anions @article{4dbba587cc7f4d1fbae7edcd05bcc4eb, title = "Wigner photoemission time delay from endohedral anions", abstract = "Characteristic features of Wigner photoemission time delay from endohedral anions A@C60q along with their dependence on the anion charge q are unraveled. Specifically, significant enhancement of the time delay in the innermost dipole photoionization channels near threshold is found, owing to the presence of the Coulomb confined resonances (CRs). Moreover, it is shown that interchannel coupling of the inner-shell Coulomb CRs with outer-shell photoionization channels results in resonantly enhanced time delay in the release of the outer-shell photoelectron well above, several hundreds eV, the outer-shell thresholds. It is also demonstrated that, and explained why, photoionization cross sections of the innermost subshells as well as outer subshells (near the inner-subshell threshold) depends only very weakly on the anion charge q, but the dependence of the corresponding time delays on q can be significant. Furthermore, Coulomb CRs are found to emerge in the innermost quadrupole photoionization channels as well, thereby causing considerable time delay in the quadrupole photoemission. These findings are illustrated in calculations of the photoionization of inner and outer subshells of the endohedral anions Ne@C60-1 and Ne@C60-5 that were chosen as case studies.", author = "Ashish Kumar and Varma, \{Hari R.\} and Deshmukh, \{Pranawa C.\} and Manson, \{Steven T.\} and Dolmatov, \{Valeriy K.\} and Anatoli Kheifets", note = "Publisher Copyright: {\textcopyright} 2016 American Physical Society. au us.", year = "2016", month = oct, day = "3", doi = "10.1103/PhysRevA.94.043401", language = "English", volume = "94", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "4", } . Physical Review A.

Attosecond Time Delay in Photoemission and Electron Scattering near Threshold @article{518768048af449ebb40e79ee478d66a1, title = "Attosecond Time Delay in Photoemission and Electron Scattering near Threshold", abstract = "We study the time delay in the primary photoemission channel near the opening of an additional channel and compare it with the Wigner time delay in elastic scattering of the photoelectron near the corresponding inelastic threshold. The photoemission time delay near threshold is significantly enhanced, to a measurable 40 as, in comparison to the corresponding elastic scattering delay. The enhancement is due to the different lowest order of interelectron interaction coupling the primary and additional photoemission channels. We illustrate these findings by considering photodetachment from the H- negative ion, and compare it with electron scattering on the hydrogen atom near the first excitation threshold. Other threshold processes of atomic photoionization and molecular photofragmentation, where photoemission time delay is enhanced, are identified. This opens the possibility of studying threshold behavior utilizing attosecond chronoscopy.", author = "Kheifets, \{Anatoli S.\} and Bray, \{Alexander W.\} and Igor Bray", note = "Publisher Copyright: {\textcopyright} 2016 American Physical Society.", year = "2016", month = sep, day = "28", doi = "10.1103/PhysRevLett.117.143202", language = "English", volume = "117", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "14", } . Physical Review Letters.

The interaction of excited atoms and few-cycle laser pulses @article{5c132d5c32634b14ab8285835ac0a9d0, title = "The interaction of excited atoms and few-cycle laser pulses", abstract = "This work describes the first observations of the ionisation of neon in a metastable atomic state utilising a strong-field, few-cycle light pulse. We compare the observations to theoretical predictions based on the Ammosov-Delone-Krainov (ADK) theory and a solution to the time-dependent Schr{\"o}dinger equation (TDSE). The TDSE provides better agreement with the experimental data than the ADK theory. We optically pump the target atomic species and measure the ionisation rate as the a function of different steady-state populations in the fine structure of the target state which shows significant ionisation rate dependence on populations of spin-polarised states. The physical mechanism for this effect is unknown.", author = "Calvert, \{J. E.\} and Han Xu and Palmer, \{A. J.\} and Glover, \{R. D.\} and Laban, \{D. E.\} and Tong, \{X. M.\} and Kheifets, \{A. S.\} and K. Bartschat and Litvinyuk, \{I. V.\} and D. Kielpinski and Sang, \{R. T.\}", note = "Publisher Copyright: {\textcopyright} The Author(s) 2016.", year = "2016", month = sep, day = "26", doi = "10.1038/srep34101", language = "English", volume = "6", journal = "Scientific Reports", issn = "2045-2322", publisher = "Nature Research", } . Scientific Reports.

Relativistic calculations of angle-dependent photoemission time delay @article{6a576d5ec1bb4c6089771ac7cb709053, title = "Relativistic calculations of angle-dependent photoemission time delay", abstract = "Angular dependence of photoemission time delay for the valence np3/2 and np1/2 subshells of Ar, Kr, and Xe is studied in the dipole relativistic random phase approximation. Strong angular anisotropy of the time delay is reproduced near respective Cooper minima while the spin-orbit splitting affects the time delay near threshold.", author = "Anatoli Kheifets and Ankur Mandal and Deshmukh, \{Pranawa C.\} and Dolmatov, \{Valeriy K.\} and Keating, \{David A.\} and Manson, \{Steven T.\}", note = "Publisher Copyright: {\textcopyright} 2016 American Physical Society.", year = "2016", month = jul, day = "25", doi = "10.1103/PhysRevA.94.013423", language = "English", volume = "94", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "1", } . Physical Review A.

Angular anisotropy of time delay in XUV+IR photoionization of H2+ @article{d2ea247736b54e06aec182adeecff6fd, title = "Angular anisotropy of time delay in XUV+IR photoionization of H2+", abstract = "We develop a technique for modeling of atomic and molecular ionization in superposition of XUV and IR fields with characteristics typical for attosecond streaking and RABBITT (reconstruction of attosecond beating by interference of two-photon transitions) experiments. The method is based on solving the time-dependent Schr{\"o}dinger equation in the coordinate frame expanding along with the photoelectron wave packet. The efficiency of the method is demonstrated by calculating angular anisotropy of photoemission time delay of the H2+ ion in a field configuration of recent RABBITT experiments.", author = "Serov, \{Vladislav V.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2016 American Physical Society.", year = "2016", month = jun, day = "17", doi = "10.1103/PhysRevA.93.063417", language = "English", volume = "93", journal = "Physical Review A", issn = "2469-9926", publisher = "American Physical Society", number = "6", } . Physical Review A.

Electron angular distributions of noble gases in sequential two-photon double ionization @article{0653bae89f8f4a35a276bdf92b364548, title = "Electron angular distributions of noble gases in sequential two-photon double ionization", abstract = "We present an angle resolved study of photoelectrons emitted from ions of the noble gases neon, argon and krypton by means of time-of-flight spectroscopy. The ionic targets are generated in a sequential two-photon process induced by the free-electron laser FLASH. Values of the anisotropy parameters β2 and β4 are derived from electron angular distribution measurements in the photon energy range from 38 to 91 eV and compared with recent theoretical calculations.", keywords = "free-electron laser, noble gases, photoelectron angular distribution, two-photon ionization", author = "M. Braune and G. Hartmann and M. Ilchen and A. Knie and T. Lischke and A. Reink{\"o}ster and A. Meissner and S. Deinert and L. Glaser and O. Al-Dossary and A. Ehresmann and Kheifets, \{A. S.\} and J. Viefhaus", note = "Publisher Copyright: {\textcopyright} 2015 Taylor \& Francis.", year = "2016", month = feb, day = "21", doi = "10.1080/09500340.2015.1047422", language = "English", volume = "63", pages = "324--333", journal = "Journal of Modern Optics", issn = "0950-0340", publisher = "Taylor and Francis Ltd.", number = "4", } . Journal of Modern Optics.

Transverse electron momentum distribution in tunneling and over the barrier ionization by laser pulses with varying ellipticity @article{64156391cb4144039379e2b3b83e6495, title = "Transverse electron momentum distribution in tunneling and over the barrier ionization by laser pulses with varying ellipticity", abstract = "We study transverse electron momentum distribution in strong field atomic ionization driven by laser pulses with varying ellipticity. We show, both experimentally and theoretically, that the transverse electron momentum distribution in the tunneling and over the barrier ionization regimes evolves in a qualitatively different way when the ellipticity parameter describing polarization state of the driving laser pulse increases.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Calvert, \{J. E.\} and S. Goodall and X. Wang and Han Xu and Palmer, \{A. J.\} and D. Kielpinski and Litvinyuk, \{I. V.\} and Sang, \{R. T.\}", year = "2016", month = jan, day = "7", doi = "10.1038/srep19002", language = "English", volume = "6", journal = "Scientific Reports", issn = "2045-2322", publisher = "Nature Research", } . Scientific Reports.

Kheifets, Anatoli, Mandal, Ankur, Deshmukh, Pranawa C., Dolmatov, Valeriy K., Keating, David A., Manson, Steven T.(2016). Relativistic calculations of angle-dependent photoemission time delay . Physical Review a. 94. (1).

Heuser, Sebastian, Galan, Alvaro Jimenez, Cirelli, Claudio, Marante, Carlos, Sabbar, Mazyar, Boge, Robert, Lucchini, Matteo, Gallmann, Lukas, Ivanov, Igor, Kheifets, Anatoli S., et al. (2016). Angular dependence of photoemission time delay in helium . Physical Review A.

Vladislav V. Serov, A. S. Kheifets (2016). Angular anisotropy of time delay in XUV plus IR photoionization of H-2(+) . Physical Review A.

Serov, Vladislav V., Kheifets, A. S.(2016). Angular anisotropy of time delay in XUV plus IR photoionization of H-2(+) . Physical Review a. 93. (6).

Calvert, J. E., Xu, Han, Palmer, A. J., Glover, R. D., Laban, D. E., Tong, X. M., Kheifets, A. S., Bartschat, K., Litvinyuk, I. V., Kielpinski, D., et al. (2016). The interaction of excited atoms and few-cycle laser pulses . Scientific Reports.

Kheifets, Anatoli S., Bray, Alexander W., Bray, Igor (2016). Attosecond Time Delay in Photoemission and Electron Scattering near Threshold . Physical Review Letters.

Calvert, J. E., Xu, Han, Palmer, A. J., Glover, R. D., Laban, D. E., Tong, X. M., Kheifets, A. S., Bartschat, K., Litvinyuk, I. V., Kielpinski, D., et al.(2016). The interaction of excited atoms and few-cycle laser pulses . Scientific Reports. 6.

Braune, M., Hartmann, G., Ilchen, M., Knie, A., Lischke, T., Reinkoester, A., Meissner, A., Deinert, S., Glaser, L., Al-Dossary, O., et al. (2016). Electron angular distributions of noble gases in sequential two-photon double ionization . Journal of Modern Optics.

Kheifets, Anatoli, Mandal, Ankur, Deshmukh, Pranawa C., Dolmatov, Valeriy K., Keating, David A., Manson, Steven T. (2016). Relativistic calculations of angle-dependent photoemission time delay . Physical Review A.

Kheifets, Anatoli S., Bray, Alexander W., Bray, Igor(2016). Attosecond Time Delay in Photoemission and Electron Scattering near Threshold . Physical Review Letters. 117. (14).

Braune, M., Hartmann, G., Ilchen, M., Knie, A., Lischke, T., Reinkoester, A., Meissner, A., Deinert, S., Glaser, L., Al-Dossary, O., et al.(2016). Electron angular distributions of noble gases in sequential two-photon double ionization . Journal of Modern Optics. 63. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 324-333.

Kheifets, Anatoli, Kumar, Ashish, Varma, Hari R., Deshmukh, Pranawa C., Manson, Steven T., Dolmatov, Valeriy K.(2016). Wigner photoemission time delay from endohedral anions . Physical Review a. 94. (4).

Kheifets, Anatoli, Kumar, Ashish, Varma, Hari R., Deshmukh, Pranawa C., Manson, Steven T., Dolmatov, Valeriy K. (2016). Wigner photoemission time delay from endohedral anions . Physical Review A.

Ivanov, I. A., Kheifets, A. S., Calvert, J. E., Goodall, S., Wang, X., Xu, Han, Palmer, A. J., Kielpinski, D., Litvinyuk, I. V., Sang, R. T. (2016). Transverse electron momentum distribution in tunneling and over the barrier ionization by laser pulses with varying ellipticity . Scientific Reports.

Heuser, Sebastian, Galan, Alvaro Jimenez, Cirelli, Claudio, Marante, Carlos, Sabbar, Mazyar, Boge, Robert, Lucchini, Matteo, Gallmann, Lukas, Ivanov, Igor, Kheifets, Anatoli S., et al.(2016). Angular dependence of photoemission time delay in helium . Physical Review a. 94. (6).

Ivanov, I. A., Kheifets, A. S., Calvert, J. E., Goodall, S., Wang, X., Xu, Han, Palmer, A. J., Kielpinski, D., Litvinyuk, I. V., Sang, R. T.(2016). Transverse electron momentum distribution in tunneling and over the barrier ionization by laser pulses with varying ellipticity . Scientific Reports. 6.

Dipole phase and photoelectron group delay in inner-shell photoionization @article{26a1b885f82d4db088d045fbb2898093, title = "Dipole phase and photoelectron group delay in inner-shell photoionization", abstract = "We conduct a systematic study of the dipole phase and the photoelectron group delay (Wigner time delay) in inner shell photoionization of noble gas atoms from Ne to Xe. Our study encompasses the tender x-ray spectral range and extends to 1 keV photoelectron energy. We employ both the relativistic and the nonrelativistic versions of the random-phase approximation with exchange. We identify the long-range Coulomb and short-range Hartree-Fock contributions to the dipole phase which governs the Wigner time delay variation from the threshold to the whole considered range of photoelectron energies.", author = "Kheifets, \{A. S.\} and S. Saha and Deshmukh, \{P. C.\} and Keating, \{D. A.\} and Manson, \{S. T.\}", note = "Publisher Copyright: {\textcopyright} 2015 American Physical Society.", year = "2015", month = dec, day = "28", doi = "10.1103/PhysRevA.92.063422", language = "English", volume = "92", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Time delay in photoionization of half-filled shell atoms @article{4db206d173094fadb289d6d4d5d0b476, title = "Time delay in photoionization of half-filled shell atoms", abstract = "Time delay in photoionization of a half-filled shell atom is predicted to be strongly term-dependent and subject to the dramatic impact of a giant autoionization resonance. Photoionization of the Mn atom is chosen as a case study.", author = "Dolmatov, \{V. K.\} and Kheifets, \{A. S.\} and Manson, \{S. T.\} and Deshmukh, \{P. C.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092004", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

A time-dependent analysis of transfer ionization in one-dimensional kinematics @article{9d1b41f4cbfd47cbbeb5fa2e29b6397f, title = "A time-dependent analysis of transfer ionization in one-dimensional kinematics", abstract = "We analyze a transfer ionization (TI) reaction in the fast proton-helium collision H+ + He → H0 + He2+ + e- by solving a time-dependent Schr{\"o}dinger equation (TDSE) under the classical projectile motion approximation in one-dimensional kinematics. By comparing results of the TDSE and various perturbative Born series calculations, we conclude that the recent discrepancies of experimental and theoretical data may be attributed to deficiency of the Born models used by other authors. We demonstrate that the correct Born series for TI should include the momentum space overlap between the double ionization amplitude and the wave function of the transferred electron.", author = "Serov, \{Vladialv V.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/2/022009", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "2", } . Journal of Physics: Conference Series.

Transverse electron momentum distribution of spin orbit wave packets @article{9b8a70e65a444a3fb79ad5b07e007c6f, title = "Transverse electron momentum distribution of spin orbit wave packets", abstract = "Transverse electron momentum distribution (TEMD) of the spin-orbit wave packets launched in a pump-probe sequential double ionization from the valence shell of Ar is calculated by solving the time-dependent Schrodinger equation (TDSE). Results are compared with a simple tunneling formula and recent measurements.", author = "Kheifets, \{A. S.\} and Ivanov, \{I. A.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092006", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Effect of coulomb confinement resonances on time delay in Ne@C60-5 @article{5b2dfae062394c38a43a91db12cb5903, title = "Effect of coulomb confinement resonances on time delay in Ne@C60-5", abstract = "Wigner time delay for inner and outer shells of Ne@C60-5 have been studied using relativistic random phase approximation (RRPA) [1]. Coulomb confinement resonances (CCR) due to the charged nature of fullerene cause prominent effects on the photoionization time delay of 1s subshell. These CCRs in 1s also results in significant modifications of the time delay in 2s and 2p ionization channels through interchannel coupling at energies far above their thresholds.", author = "Ashish Kumar and Varma, \{H. R.\} and Deshmukh, \{P. C.\} and Manson, \{S. T.\} and Dolmatov, \{V. K.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092042", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Transverse electron momentum distribution in strong field ionization @article{60a6cff645994e3ba823e6fc09217df3, title = "Transverse electron momentum distribution in strong field ionization: Transition from tunneling to over the barrier ionization regimes", abstract = "We study transverse electron momentum distribution (TEMD) in strong field atomic ionization driven by laser pulses with varying ellipticity. We show, that the TEMD in the tunneling and over the barrier ionization regimes evolves in a qualitatively different way when the ellipticity parameter describing polarization state of the driving laser pulse increases.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092077", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Wigner time delay studies of photoionization of atomic zinc and cadmium @article{fb64bb0e2d0649ec9615916cf3308cfc, title = "Wigner time delay studies of photoionization of atomic zinc and cadmium", abstract = "Wigner time delay has been studied in the shape resonance region for the outer nd→εf photoionization transitions in atomic Zn and Cd.", author = "S. Saha and A. Mandal and Deshmukh, \{P. C.\} and A. Kheifets and Dolmatov, \{V. K.\} and Manson, \{S. T.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092061", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Pulse-shape effects in strong-field atomic ionization by an XUV pulse @article{1c64eb35564a4c0b8c5fdccdd493db1b, title = "Pulse-shape effects in strong-field atomic ionization by an XUV pulse", abstract = "Achieving a significant displacement, defined as a time integral of the vector potential taken over the pulse duration, in strong-field atomic ionization critically depends on the envelope function used for the electric field. Due to the sensitivity of theoretical predictions to the pulse details, an experimental realization of the effect appears to be a major challenge.", author = "Klaus Bartschat and Joel Venzke and John Emmons and Sean Buczek and Grum-Grzhimailo, \{Alexei N.\} and Gryzlova, \{Elena V.\} and Ivanov, \{Igor A.\} and Kheifets, \{Anatoli S.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092021", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Time delay anisotropy in photoelectron emission from isotropic helium @article{9a313fccc91d4c1caee746a657158a18, title = "Time delay anisotropy in photoelectron emission from isotropic helium", abstract = "In contrast to expectations, we observe that the photoionization time delay from the 1s2 spherically symmetric ground state of He depend on the electron emission direction with respect to an external reference. We attribute the observed anisotropy to the interplay between different final quantum states, which become accessible once two photons are involved in the photoionization process. This is a universal effect, which needs to be taken into account for any study dealing with photoionization dynamics.", author = "S. Heuser and Jim{\'e}nez-G{\'a}lan and C. Cirelli and M. Sabbar and R. Boge and M. Lucchini and L. Gallmann and I. Ivanov and A. Kheifets and Dahlstr{\"o}m, \{J. M.\} and E. Lindroth and L. Argenti and F. Mart{\'i}n and U. Keller", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092089", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Wigner time delay in quadrupole photoionization channels of atomic Hg @article{aa773d213a79453ea47dfced5998875a, title = "Wigner time delay in quadrupole photoionization channels of atomic Hg", abstract = "Time delay in quadrupole (E2) channels is studied in atomic Hg using the Relativistic Random Phase Approximation. Interchannel coupling is found to be extremely important and large time delays are found in the region of quadrupole (E2) Cooper minima.", author = "Ankur Mandal and Soumyajit Saha and Tanima Banerjee and Deshmukh, \{Pranawa C.\} and Anatoli Kheifets and Dolmatov, \{Valeriy K.\} and Manson, \{Steven T.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092097", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Transverse electron momentum distribution in tunneling and over the barrier ionization by strong-field laser pulses @article{dbdf99c711e9456b82e7e1722f2929f4, title = "Transverse electron momentum distribution in tunneling and over the barrier ionization by strong-field laser pulses", abstract = "We present the results of an investigation of the measurement of the transverse electron momentum (TEMD) distribution of atoms ionized though the interaction of strong-field light pulses of varying ellipticity. We show though experiment and theory that the TEMD for the tunneling regime and the over-the-barrier regime (OB) evolves in a qualitatively different way when polarization state of the ionizing laser changes ellipticity.", author = "Calvert, \{J. E.\} and S. Goodall and X. Wang and Han Xu and Palmer, \{A. J.\} and Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and D. Kielpinski and Litvinyuk, \{I. V.\} and Sang, \{R. T.\}", note = "Publisher Copyright: {\textcopyright} Published under licence by IOP Publishing Ltd.; 29th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2015 ; Conference date: 22-07-2015 Through 28-07-2015", year = "2015", month = sep, day = "7", doi = "10.1088/1742-6596/635/9/092073", language = "English", volume = "635", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "9", } . Journal of Physics: Conference Series.

Interpreting attoclock measurements of tunnelling times @article{96c11e97fa67471dab7c24e211794f7d, title = "Interpreting attoclock measurements of tunnelling times", abstract = "Resolving in time the dynamics of light absorption by atoms and molecules, and the electronic rearrangement this induces, is among the most challenging goals of attosecond spectroscopy. The attoclock is an elegant approach to this problem, which encodes ionization times in the strong-field regime. However, the accurate reconstruction of these times from experimental data presents a formidable theoretical task. Here, we solve this problem by combining analytical theory with ab initio numerical simulations. We apply our theory to numerical attoclock experiments on the hydrogen atom to extract ionization time delays and analyse their nature. Strong-field ionization is often viewed as optical tunnelling through the barrier created by the field and the core potential. We show that, in the hydrogen atom, optical tunnelling is instantaneous. We also show how calibrating the attoclock using the hydrogen atom opens the way to identifying possible delays associated with multielectron dynamics during strong-field ionization.", author = "Lisa Torlina and Felipe Morales and Jivesh Kaushal and Igor Ivanov and Anatoli Kheifets and Alejandro Zielinski and Armin Scrinzi and Muller, \{Harm Geert\} and Suren Sukiasyan and Misha Ivanov and Olga Smirnova", note = "Publisher Copyright: {\textcopyright} 2015 Macmillan Publishers Limited. All rights reserved.", year = "2015", month = jun, day = "4", doi = "10.1038/nphys3340", language = "English", volume = "11", pages = "503--508", journal = "Nature Physics", issn = "1745-2473", publisher = "Nature Research", number = "6", } . Nature Physics.

Attosecond time delay in the photoionization of Mn in the region of the 3p → 3d giant resonance @article{10264d7e477748cd85d6d36d9e7250ba, title = "Attosecond time delay in the photoionization of Mn in the region of the 3p → 3d giant resonance", abstract = "Initial insight into time delay in Mn photoionization in the region of the 3p →, 3d giant autoionization resonance is gained in the framework of the {"}spin-polarized{"} random-phase approximation with exchange. The dramatic effect of the giant autoionization resonance on the time delay of photoemission from the 3d and 4s valence subshells of the Mn atom is unraveled. Strong sensitivity of the time delay of the 4s photoemission to the final-state term of the ion remainder [Mn+(4s1,5S) vs Mn+(4s1,7S)] is discovered. It is shown that photoionization time delay in the autoionizing resonance region is explicitly associated with the resonance lifetime, which can thus be directly measured in attosecond time-delay experiments. Similar features are expected to emerge in photoionization time delays of other transition-metal and rare-earth atoms with half-filled subshells that possess giant autoionization resonances as well.", author = "Dolmatov, \{V. K.\} and Kheifets, \{A. S.\} and Deshmukh, \{P. C.\} and Manson, \{S. T.\}", note = "Publisher Copyright: {\textcopyright} 2015 American Physical Society.", year = "2015", month = may, day = "18", doi = "10.1103/PhysRevA.91.053415", language = "English", volume = "91", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Kheifets, Anatoli, Torlina, Lisa, Morales, Felipe, Kaushal, Jivesh, Ivanov, Igor, Zielinski, Alejandro, Scrinzi, Armin, Muller, Harm Geert, Sukiasyan, Suren, Ivanov, Misha, et al. (2015). Interpreting attoclock measurements of tunnelling times . Nature Physics.

Kheifets, Anatoli, Torlina, Lisa, Morales, Felipe, Kaushal, Jivesh, Ivanov, Igor, Zielinski, Alejandro, Scrinzi, Armin, Muller, Harm Geert, Sukiasyan, Suren, Ivanov, Misha, et al.(2015). Interpreting attoclock measurements of tunnelling times . Nature Physics. 11. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 503-U86.

Dolmatov, V. K., Kheifets, A. S., Deshmukh, P. C., Manson, S. T. (2015). Attosecond time delay in the photoionization of Mn in the region of the 3p -> 3d giant resonance . Physical Review A.

Dolmatov, V. K., Kheifets, A. S., Deshmukh, P. C., Manson, S. T.(2015). Attosecond time delay in the photoionization of Mn in the region of the 3p -> 3d giant resonance . Physical Review a. 91. (5).

Kheifets, A. S., Saha, S., Deshmukh, P. C., Keating, D. A., Manson, S. T.(2015). Dipole phase and photoelectron group delay in inner-shell photoionization . Physical Review a. 92. (6).

Kheifets, A. S., Saha, S., Deshmukh, P. C., Keating, D. A., Manson, S. T. (2015). Dipole phase and photoelectron group delay in inner-shell photoionization . Physical Review A.

Measurements of relative photoemission time delays in noble gas atoms @article{c6241b12262340838ba31f4f7a9b0197, title = "Measurements of relative photoemission time delays in noble gas atoms", abstract = "We determine relative photoemission time delays between valence electrons in different noble gas atoms (Ar, Ne and He) in an energy range between 31 and 37 eV. The atoms are ionized by an attosecond pulse train synchronized with an infrared laser field and the delays are measured using an interferometric technique. We compare our results with calculations using the random phase approximation with exchange and multi-configurational Hartree-Fock. We also investigate the influence of the different ionization angular channels.", keywords = "MCHF, RABITT, RPAE, attosecond, photoemission time delay", author = "D. Gu{\'e}not and D. Kroon and E. Balogh and Larsen, \{E. W.\} and M. Kotur and M. Miranda and T. Fordell and P. Johnsson and J. Mauritsson and M. Gisselbrecht and K. Varj{\'u} and Arnold, \{C. L.\} and T. Carette and Kheifets, \{A. S.\} and E. Lindroth and A. Lhuillier and Dahlstr{\"o}m, \{J. M.\}", note = "Publisher Copyright: {\textcopyright} 2014 IOP Publishing Ltd.", year = "2014", month = dec, day = "28", doi = "10.1088/0953-4075/47/24/245602", language = "English", volume = "47", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "24", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Atomic delay in helium, neon, argon and krypton @article{0106dd2859994408895cd62dcd425f53, title = "Atomic delay in helium, neon, argon and krypton", abstract = "Photoionization by an eXtreme UltraViolet (XUV) attosecond pulse train (APT) in the presence of an infrared pulse (RABBITT method) conveys information about the atomic photoionization delay. By taking the difference of the spectral delays between pairs of rare gases (Ar,He), (Kr,He) and (Ne,He) it is possible to eliminate in each case the larger group delay ('attochirp') associated with the APT itself and obtain the Ar, Kr and Ne Wigner delays referenced to model calculations of the He delay. In this work we measure how the delays vary as a function of XUV photon energy but we cannot determine the absolute delay difference between atoms due to lack of precise knowledge of the initial conditions. The extracted delays are compared with several theoretical predictions and the results are consistent within 30 as over the energy range from 10 to 50 eV. An 'effective' Wigner delay over all emission angles is found to be more consistent with our angle-integrated measurement near the Cooper minimum in Ar. We observe a few irregular features in the delay that may be signatures of resonances.", keywords = "attosecond, delay, photoionization", author = "Caryn Palatchi and Dahlstr{\"o}m, \{J. M.\} and Kheifets, \{A. S.\} and Ivanov, \{I. A.\} and Canaday, \{D. M.\} and P. Agostini and Dimauro, \{L. F.\}", note = "Publisher Copyright: {\textcopyright} 2014 IOP Publishing Ltd.", year = "2014", month = dec, day = "28", doi = "10.1088/0953-4075/47/24/245003", language = "English", volume = "47", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "24", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Time-dependent calculations of transfer ionization by fast proton-helium collision in one-dimensional kinematics @article{845642fa1aec4ca69eb7a002f545ca29, title = "Time-dependent calculations of transfer ionization by fast proton-helium collision in one-dimensional kinematics", abstract = "We analyze a transfer ionization (TI) reaction in the fast proton-helium collision H++He→H0+He2++ e- by solving a time-dependent Schr{\"o}dinger equation (TDSE) under the classical projectile motion approximation in one-dimensional kinematics. In addition, we construct various time-independent analogs of our model using lowest-order perturbation theory in the form of the Born series. By comparing various aspects of the TDSE and the Born series calculations, we conclude that the recent discrepancies of experimental and theoretical data may be attributed to deficiency of the Born models used by other authors. We demonstrate that the correct Born series for TI should include the momentum-space overlap between the double-ionization amplitude and the wave function of the transferred electron.", author = "Serov, \{Vladislav V.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} 2014 American Physical Society.", year = "2014", month = dec, day = "8", doi = "10.1103/PhysRevA.90.062706", language = "English", volume = "90", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Laser-sub-cycle two-dimensional electron-momentum mapping using orthogonal two-color fields @article{ead2c0c61577429a95a61527ba2f1e8a, title = "Laser-sub-cycle two-dimensional electron-momentum mapping using orthogonal two-color fields", abstract = "We study laser-sub-cycle control over electron trajectories concomitantly in space and time using orthogonally polarized two-color laser fields. We compare experimental photoelectron spectra of neon recorded by coincidence momentum imaging with photoelectron spectra obtained by semiclassical and numerical solutions of the time-dependent Schr{\"o}dinger equation. We find that a resolution of a quarter optical cycle in the photoelectron trajectories can be achieved. It is shown that depending on their sub-cycle birth time the trajectories of photoelectrons are affected differently by the ion's Coulomb field.", author = "Li Zhang and Xinhua Xie and Stefan Roither and Daniil Kartashov and Yanlan Wang and Chuanliang Wang and Markus Sch{\"o}ffler and Dror Shafir and Corkum, \{Paul B.\} and Andrius Baltu{\v s}ka and Igor Ivanov and Anatoli Kheifets and Xiaojun Liu and Andr{\'e} Staudte and Markus Kitzler", note = "Publisher Copyright: {\textcopyright} 2014 American Physical Society.", year = "2014", month = dec, day = "1", doi = "10.1103/PhysRevA.90.061401", language = "English", volume = "90", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Relativistic effects in photoionization time delay near the Cooper minimum of noble-gas atoms @article{0f5333c7bfa744b181fa94d193c9644b, title = "Relativistic effects in photoionization time delay near the Cooper minimum of noble-gas atoms", abstract = "Time delay of photoemission from valence ns, np3/2, and np1/2 subshells of noble-gas atoms is theoretically scrutinized within the framework of the dipole relativistic random phase approximation. The focus is on the variation of time delay in the vicinity of the Cooper minima in photoionization of the outer subshells of neon, argon, krypton, and xenon, where the corresponding dipole matrix element changes its sign while passing through a node. It is revealed that the presence of the Cooper minimum in one photoionization channel has a strong effect on time delay in other channels. This is shown to be due to interchannel coupling.", author = "Soumyajit Saha and Ankur Mandal and Jobin Jose and Varma, \{Hari R.\} and Deshmukh, \{P. C.\} and Kheifets, \{A. S.\} and Dolmatov, \{V. K.\} and Manson, \{S. T.\}", note = "Publisher Copyright: {\textcopyright} 2014 American Physical Society.", year = "2014", month = nov, day = "6", doi = "10.1103/PhysRevA.90.053406", language = "English", volume = "90", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Displacement effect in strong-field atomic ionization by an XUV pulse @article{a209d142d17c40b9a553b68455ec09d4, title = "Displacement effect in strong-field atomic ionization by an XUV pulse", abstract = "We study strong-field atomic ionization driven by an XUV pulse with a nonzero displacement, the quantity defined as the time integral of the pulse vector potential taken over the pulse duration. The use of such pulses may lead to an extreme sensitivity of the ionization process to subtle changes of a driving XUV pulse, in particular, the ramp-on and off profile and the carrier envelope phase. We illustrate this sensitivity for atomic hydrogen and lithium driven by few-femtosecond XUV pulses with intensity in the 1014W/cm2 range. The observed effect is general and should modify strong-field ionization of any atom or molecule, provided the ionization rate is sufficiently high.", author = "Ivanov, \{Igor A.\} and Kheifets, \{Anatoli S.\} and Klaus Bartschat and John Emmons and Buczek, \{Sean M.\} and Gryzlova, \{Elena V.\} and Grum-Grzhimailo, \{Alexei N.\}", note = "Publisher Copyright: {\textcopyright} 2014 American Physical Society.", year = "2014", month = oct, day = "3", doi = "10.1103/PhysRevA.90.043401", language = "English", volume = "90", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "4", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Transverse-electron-momentum distribution in pump-probe sequential double ionization @article{ea6f42e9fa4a4b28832b37919b81973b, title = "Transverse-electron-momentum distribution in pump-probe sequential double ionization", abstract = "We study the transverse-electron-momentum distribution (TEMD) of the wave packets launched in a pump-probe sequential double ionization from the valence shell of a noble gas atom. Our calculations, based on an accurate numerical solution of the time-dependent Schr{\"o}dinger equation (TDSE), reproduce a characteristic cusp of the TEMD which is attributed to the Coulomb singularity. The evolution of the TEMD with the time delay between the pump and probe pulses is shown to be similar to the prediction of the standard tunneling formula (TF), as was observed experimentally for argon by Fechner et al. [Phys. Rev. Lett. 112, 213001 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.213001]. However, TDSE calculations show a clear deviation from the TF and predict a much more complicated structure which cannot be reproduced by the target orbital momentum profile filtered by the tunneling Gaussian. The accuracy of the TF can be improved if the target momentum profile is calculated with the Coulomb waves instead of the plane waves.", author = "Kheifets, \{A. S.\} and Ivanov, \{I. A.\}", note = "Publisher Copyright: {\textcopyright} 2014 American Physical Society.", year = "2014", month = sep, day = "5", doi = "10.1103/PhysRevA.90.033404", language = "English", volume = "90", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "3", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Dissociative ionization of H2 by 400 eV circularly polarized photons @article{6dd5cdfc55df40be98f2255c67d87e97, title = "Dissociative ionization of H2 by 400 eV circularly polarized photons", abstract = "Calculations of single photon one-electron ionization-dissociation of H2 are performed ab initio with accurate quantum mechanical description of the nuclear motion. The clear interference pattern is observed in the photoelectron angular distribution detected in the molecular frame. An effect of this interference on the dissociation process is found.", keywords = "dissociation, ionization, molecular hydrogen", author = "Serov, \{Vladislav V.\} and Kheifets, \{A. S.\}", year = "2014", month = jun, day = "14", doi = "10.1088/0953-4075/47/11/115006", language = "English", volume = "47", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "11", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Attosecond time delay in the photoionization of endohedral atoms A@C60 @article{4cf7b248896e409583439b8bd9df7f64, title = "Attosecond time delay in the photoionization of endohedral atoms A@C60: A probe of confinement resonances", abstract = "The effects of confinement resonances on photoelectron group delay (Wigner time delay) following ionization of an atom encapsulated inside a C60 cage have been studied theoretically using both relativistic and nonrelativistic random phase approximations. The results indicate clearly the resonant character of the confinement oscillations in time delay of the 4d shell of Xe@C60 and present a most direct manifestation of Wigner time delay. These oscillations were missed in a previous theoretical investigation of Ar@C60 [Phys. Rev. Lett. 111, 203003 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.203003].", author = "Deshmukh, \{P. C.\} and A. Mandal and S. Saha and Kheifets, \{A. S.\} and Dolmatov, \{V. K.\} and Manson, \{S. T.\}", year = "2014", month = may, day = "29", doi = "10.1103/PhysRevA.89.053424", language = "English", volume = "89", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Relativistic effects in time delay of atomic photoionization @article{900a47f41ddd473d99177fc1f6d44561, title = "Relativistic effects in time delay of atomic photoionization", abstract = "We study relativistic effects in the time delay of atomic photoionization using an example of the Xe atom subjected to a circularly polarized electromagnetic pulse. We find that while relativistic effects play only a fairly small role for both the ionization probabilities and the time delay of the corotating electron with the same sign of the angular momentum projection as the circularly polarized light, these effects produce substantial change in the time delay for a counter-rotating electron with the opposite sign of the angular momentum projection.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2014", month = apr, day = "7", doi = "10.1103/PhysRevA.89.043405", language = "English", volume = "89", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "4", } . Physical Review A - Atomic, Molecular, and Optical Physics.

P -H symmetry breaking in dissociative photoionization of H2 due to the molecular ion interacting with the ejected electron @article{d4f297bbb35b45cba19c8511c47ade6d, title = "P -H symmetry breaking in dissociative photoionization of H2 due to the molecular ion interacting with the ejected electron", abstract = "We propose a mechanism of electron localization and molecular symmetry breaking in dissociative photoionization of the H2 molecule. The Coulomb field of the ejected electron can induce the transition of the remaining H2+ ion from the gerade 2Σg 1(1sσg) to the ungerade 2Σ u1(2pσu) electronic state when the nuclei in a bound vibrational state are near the outer turning point. The superposition of this process with a direct transition to the vibrational continuum should produce a nongerade ionic state, which results in observed asymmetry in the p-H ejection relative to the electron ejection direction at a small kinetic energy release.", author = "Serov, \{Vladislav V.\} and Kheifets, \{A. S.\}", year = "2014", month = mar, day = "7", doi = "10.1103/PhysRevA.89.031402", language = "English", volume = "89", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "3", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Double ionization probed on the attosecond timescale @article{44a70f0add194967b73b8e1e7843f693, title = "Double ionization probed on the attosecond timescale", abstract = "Double ionization following the absorption of a single photon is one of the most fundamental processes requiring interaction between electrons. Information about this interaction is usually obtained by detecting emitted particles without access to real-time dynamics. Here, attosecond light pulses, electron wave packet interferometry and coincidence techniques are combined to measure electron emission times in double ionization of xenon using single ionization as a clock, providing unique insight into the two-electron ejection mechanism. Access to many-particle dynamics in real time is of fundamental importance for understanding processes induced by electron correlation in atomic, molecular and more complex systems.", author = "M{\aa}nsson, \{Erik P.\} and Diego Gu{\'e}not and Arnold, \{Cord L.\} and David Kroon and Susan Kasper and Dahlstr{\"o}m, \{J. Marcus\} and Eva Lindroth and Kheifets, \{Anatoli S.\} and Anne L'huillier and Sorensen, \{Stacey L.\} and Mathieu Gisselbrecht", year = "2014", month = mar, doi = "10.1038/nphys2880", language = "English", volume = "10", pages = "207--211", journal = "Nature Physics", issn = "1745-2473", publisher = "Nature Research", number = "3", } . Nature Physics.

Strong-field ionization of He by elliptically polarized light in attoclock configuration @article{6cca0b2748cc44daa53dce6131707f2d, title = "Strong-field ionization of He by elliptically polarized light in attoclock configuration", abstract = "We perform time-dependent calculations of strong-field ionization of He by elliptically polarized light in configuration of recent attoclock measurements of Boge [Phys. Rev. Lett. 111, 103003 (2013)PRLTAO0031-900710.1103/PhysRevLett. 111.103003]. By solving a three-dimensional time-dependent Schr{\"o}dinger equation, we obtain the angular offset θm of the maximum in the photoelectron momentum distribution in the polarization plane relative to the position predicted by the strong-field approximation. This offset is used in attoclock measurements to extract the tunneling time. Our calculations clearly support the set of experimental angular offset values obtained with the use of nonadiabatic calibration of the in situ field intensity, and disagree with an alternative set calibrated adiabatically. These findings are in contrast with the conclusions of Boge et al. who found a qualitative agreement of their semiclassical calculations with the adiabatic set of experimental data. This controversy may complicate interpretation of the recent attoclock measurements.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2014", month = feb, day = "11", doi = "10.1103/PhysRevA.89.021402", language = "English", volume = "89", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Photo-double-ionization of Mg studied by electron-electron-coincidence experiments @article{8088a1e6e15942f18409afb58ca0cdf1, title = "Photo-double-ionization of Mg studied by electron-electron-coincidence experiments", abstract = "The photo-double-ionization (PDI) of Mg to the Mg2+(3s-2) state has been studied by photoelectron-photoelectron-coincidence experiments at a photon energy corresponding to the excitation of the 2p→3d resonance. The equal energy sharing (E1 = E2 = 16.4 eV) as well as the complementary unequal energy (E1-E2 = 10.4-22.4 eV) sharing kinematics have been investigated. From the experimental results without any approximation the symmetrized gerade and ungerade amplitudes have been obtained. The experimental angular correlation patterns as well as the amplitudes are compared to CCC calculations in which the resonant process has been incorporated. The results confirm that the amplitudes of the photo-double-ionization carry the signature of the target radial wave function. The investigation of the triple differential cross sections has been then extended by simulations to a kinematics with the fixed detector at 90o, which can not be studied experimentally by the present setup. These simulations shed light on results of previous measurements on alkaline-earth-metal atoms in this kinematics, which were not consistent with the common understanding of photo-double-ionization derived from He experiments.", keywords = "32.80.Fb", author = "E. Sokell and P. Bolognesi and A. Kheifets and I. Bray and S. Safgren and L. Avaldi", year = "2014", month = jan, day = "21", doi = "10.1103/PhysRevA.89.013413", language = "English", volume = "89", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "1", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Deshmukh, P. C., Mandal, A., Saha, S., Kheifets, A. S., Dolmatov, V. K., Manson, S. T. (2014). Attosecond time delay in the photoionization of endohedral atoms A@C-60: A probe of confinement resonances . Physical Review A.

Ivanov, I. A., Kheifets, A. S. (2014). Relativistic effects in time delay of atomic photoionization . Physical Review A.

Two and three-photon double ionization of lithium @article{000d275fc1144c4d9324bad8ef737c90, title = "Two and three-photon double ionization of lithium", abstract = "Differential studies on two and three-photon double ionization (DI) of atomic lithium have been performed for photon energies of 50 eV and 59 eV at I 5 × 1013 W/cm2. At 50 eV DI proceeds via the simultaneous absorption of two photons resulting in the correlated emission of two electrons. In contrast for a photon energy of 59 eV, the resonant one photon transition (1s 2p) is followed by DI through a second photon. Additionally a competing sequential three photon reaction is observed for both energies. The experimental data is compared with results from non-perturbative close-coupling calculations.", author = "Michael Schuricke and Christian Dornes and Gregory Armstrong and James Colgan and Anatoli Kheifets and Joachim Ullrich and Alexander Dorn", year = "2014", doi = "10.1088/1742-6596/488/3/032032", language = "English", volume = "488", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "SECTION 3", note = "28th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2013 ; Conference date: 24-07-2013 Through 30-07-2013", } . Journal of Physics: Conference Series.

Two-electron interference in angular resolved double photoionization of Mg @article{6694539662e14c0d9f96047f9fd81bf5, title = "Two-electron interference in angular resolved double photoionization of Mg", abstract = "We observe a two-electron interference effect in the symmetrized amplitude of the resonant double photoionization of Mg which was predicted theoretically, but never before observed experimentally. This observation is based on our experimental study of angle-resolved double photoionization of Mg at the photon energy of 55.49 eV (2p → 3d resonance) under equal and unequal energy sharing conditions.", author = "E. Sokell and P. Bolognesi and A. Kheifets and Igor Bray and S. Safgren and L. Avaldi", year = "2014", doi = "10.1088/1742-6596/488/2/022006", language = "English", volume = "488", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "SECTION 2", note = "28th International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC 2013 ; Conference date: 24-07-2013 Through 30-07-2013", } . Journal of Physics: Conference Series.

Ivanov, Igor A., Kheifets, Anatoli S., Bartschat, Klaus, Emmons, John, Buczek, Sean M., Gryzlova, Elena V., Grum-Grzhimailo, Alexei N.(2014). Displacement effect in strong-field atomic ionization by an XUV pulse . Physical Review a. 90. (4).

Palatchi, Caryn, Dahlstrom, J. M., Kheifets, A. S., Ivanov, I. A., Canaday, D. M., Agostini, P., DiMauro, L. F. (2014). Atomic delay in helium, neon, argon and krypton . Journal of Physics B: Atomic, Molecular and Optical Physics.

Serov, Vladislav V., Kheifets, A. S.(2014). Dissociative ionization of H-2 by 400 eV circularly polarized photons . Journal of Physics B-Atomic Molecular and Optical Physics. 47. (11).

Palatchi, Caryn, Dahlstrom, J. M., Kheifets, A. S., Ivanov, I. A., Canaday, D. M., Agostini, P., DiMauro, L. F.(2014). Atomic delay in helium, neon, argon and krypton . Journal of Physics B-Atomic Molecular and Optical Physics. 47. (24).

Sokell, E., Bolognesi, P., Kheifets, A., Bray, I., Safgren, S., Avaldi, L. (2014). Photo-double-ionization of Mg studied by electron-electron-coincidence experiments . Physical Review A.

Kheifets, Anatoli, Zhang, Li, Xie, Xinhua, Roither, Stefan, Kartashov, Daniil, Wang, YanLan, Wang, ChuanLiang, Schoeffler, Markus, Shafir, Dror, Corkum, Paul B., et al. (2014). Laser-sub-cycle two-dimensional electron-momentum mapping using orthogonal two-color fields . Physical Review A.

Saha, Soumyajit, Mandal, Ankur, Jose, Jobin, Varma, Hari R., Deshmukh, P. C., Kheifets, A. S., Dolmatov, V. K., Manson, S. T. (2014). Relativistic effects in photoionization time delay near the Cooper minimum of noble-gas atoms . Physical Review A.

Kheifets, A. S., Ivanov, I. A.(2014). Transverse-electron-momentum distribution in pump-probe sequential double ionization . Physical Review a. 90. (3).

Sokell, E., Bolognesi, P., Kheifets, A., Bray, I., Safgren, S., Avaldi, L.(2014). Photo-double-ionization of Mg studied by electron-electron-coincidence experiments . Physical Review a. 89. (1).

Mansson, Erik P., Guenot, Diego, Arnold, Cord L., Kroon, David, Kasper, Susan, Dahlstrom, J. Marcus, Lindroth, Eva, Kheifets, Anatoli S., L&#39;Huillier, Anne, Sorensen, Stacey L., et al.(2014). Double ionization probed on the attosecond timescale . Nature Physics. 10. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 207-211.

Serov, Vladislav V., Kheifets, A. S.(2014). Time-dependent calculations of transfer ionization by fast proton-helium collision in one-dimensional kinematics . Physical Review a. 90. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2706.

Kheifets, Anatoli, Zhang, Li, Xie, Xinhua, Roither, Stefan, Kartashov, Daniil, Wang, YanLan, Wang, ChuanLiang, Schoeffler, Markus, Shafir, Dror, Corkum, Paul B., et al.(2014). Laser-sub-cycle two-dimensional electron-momentum mapping using orthogonal two-color fields . Physical Review a. 90. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1401.

Ivanov, I. A., Kheifets, A. S.(2014). Relativistic effects in time delay of atomic photoionization . Physical Review a. 89. (4).

Saha, Soumyajit, Mandal, Ankur, Jose, Jobin, Varma, Hari R., Deshmukh, P. C., Kheifets, A. S., Dolmatov, V. K., Manson, S. T.(2014). Relativistic effects in photoionization time delay near the Cooper minimum of noble-gas atoms . Physical Review a. 90. (5).

Mansson, Erik P., Guenot, Diego, Arnold, Cord L., Kroon, David, Kasper, Susan, Dahlstrom, J. Marcus, Lindroth, Eva, Kheifets, Anatoli S., L&#39;Huillier, Anne, Sorensen, Stacey L., et al. (2014). Double ionization probed on the attosecond timescale . Nature Physics.

Vladislav V. Serov, A. S. Kheifets (2014). Time-dependent calculations of transfer ionization by fast proton-helium collision in one-dimensional kinematics . Physical Review A.

Ivanov, I. A., Kheifets, A. S.(2014). Strong-field ionization of He by elliptically polarized light in attoclock configuration . Physical Review a. 89. (2).

A. S. Kheifets(2014). Atto-second time-delay in single and double photoionization of noble gas atoms . Journal of Physics: Conference Series. 488. (SECTION 3). IOP Publishing Ltd.

Serov, Vladislav V., Kheifets, A. S.(2014). p-H symmetry breaking in dissociative photoionization of H-2 due to the molecular ion interacting . Physical Review a. 89. (3).

Vladislav V. Serov, A. S. Kheifets (2014). p-H symmetry breaking in dissociative photoionization of H-2 due to the molecular ion interacting . Physical Review A.

Guenot, D., Kroon, D., Balogh, E., Larsen, E. W., Kotur, M., Miranda, M., Fordell, T., Johnsson, P., Mauritsson, J., Gisselbrecht, M., et al. (2014). Measurements of relative photoemission time delays in noble gas atoms . Journal of Physics B: Atomic, Molecular and Optical Physics.

Kheifets, A. S., Ivanov, I. A. (2014). Transverse-electron-momentum distribution in pump-probe sequential double ionization . Physical Review A.

E. Sokell, P. Bolognesi, A. Kheifets, I. Bray, S. Safgren, L. Avaldi(2014). Two electron interference in angular resolved double photoionization of Mg . Journal of Physics: Conference Series. 488. (SECTION 1). IOP Publishing Ltd.

Vladislav V Serov, A S Kheifets (2014). Dissociative ionization of H-2 by 400 eV circularly polarized photons . Journal of Physics B: Atomic, Molecular and Optical.

Guenot, D., Kroon, D., Balogh, E., Larsen, E. W., Kotur, M., Miranda, M., Fordell, T., Johnsson, P., Mauritsson, J., Gisselbrecht, M., et al.(2014). Measurements of relative photoemission time delays in noble gas atoms . Journal of Physics B-Atomic Molecular and Optical Physics. 47. (24).

M. S. Sch&#246;ffler, T. Jahnke, M. Waitz, F. Trinter, U. Lenz, C. Stuck, M. Jones, M. S. Pindzola, A. Belkacem, C. L. Cocke, et al.(2014). Single photon double ionization of Helium at 800 eV-observation of the Quasi Free Mechanism . Journal of Physics: Conference Series. 488. (SECTION 2). IOP Publishing Ltd.

Ivanov, Igor A., Kheifets, Anatoli S., Bartschat, Klaus, Emmons, John, Buczek, Sean M., Gryzlova, Elena V., Grum-Grzhimailo, Alexei N. (2014). Displacement effect in strong-field atomic ionization by an XUV pulse . Physical Review A.

Ivanov, I. A., Kheifets, A. S. (2014). Strong-field ionization of He by elliptically polarized light in attoclock configuration . Physical Review A.

A. S. Kheifets, I. A. Ivanov(2014). Time delay in atomic photoionization with circularly polarized light . Journal of Physics: Conference Series. 488. (SECTION 3). IOP Publishing Ltd.

Deshmukh, P. C., Mandal, A., Saha, S., Kheifets, A. S., Dolmatov, V. K., Manson, S. T.(2014). Attosecond time delay in the photoionization of endohedral atoms A@C-60: A probe of confinement resonances . Physical Review a. 89. (5).

Ejection of quasi-free-electron pairs from the helium-atom ground state by single-photon absorption @article{8f7d2cd8b28f4ad0ac1f370a97f7582a, title = "Ejection of quasi-free-electron pairs from the helium-atom ground state by single-photon absorption", abstract = "We investigate the single-photon double ionization of helium at photon energies of 440 and 800 eV. We observe doubly charged ions with close to zero momentum corresponding to electrons emitted back to back with equal energy. These slow ions are the unique fingerprint of an elusive quasifree photon double ionization mechanism predicted by Amusia et al. nearly four decades ago. It results from the nondipole part of the electromagnetic interaction. Our experimental data are supported by calculations performed using the convergent close-coupling and time-dependent close-coupling methods.", author = "Sch{\"o}ffler, \{M. S.\} and C. Stuck and M. Waitz and F. Trinter and T. Jahnke and U. Lenz and M. Jones and A. Belkacem and Landers, \{A. L.\} and Pindzola, \{M. S.\} and Cocke, \{C. L.\} and J. Colgan and A. Kheifets and I. Bray and H. Schmidt-B{\"o}cking and R. D{\"o}rner and Th Weber", year = "2013", month = jul, day = "2", doi = "10.1103/PhysRevLett.111.013003", language = "English", volume = "111", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "1", } . Physical Review Letters.

Extraction of the attosecond time delay in atomic photoionization using the soft-photon approximation @article{d1c208eef6924aa08aa4449a729a0e31, title = "Extraction of the attosecond time delay in atomic photoionization using the soft-photon approximation", abstract = "We use the soft-photon approximation to extract the Wigner time delay from atomic two-color photoionization experiments. Unlike the strong-field approximation, the present method does not require introduction of the Coulomb-laser coupling corrections and enables one to extract the Wigner time delay directly from attosecond time delay measurements.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2013", month = jun, day = "20", doi = "10.1103/PhysRevA.87.063419", language = "English", volume = "87", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Time delay in valence-shell photoionization of noble-gas atoms @article{f8caf1d3fbac460caf82fa5034c256cb, title = "Time delay in valence-shell photoionization of noble-gas atoms", abstract = "We use the nonrelativistic random-phase approximation with exchange to perform calculations of valence-shell photoionization of Ne, Ar, Kr, and Xe from their respective thresholds to photon energy of 200 eV. The energy derivative of the complex phase of the photoionization matrix elements is converted to the photoelectron group delay that can be measured in attosecond streaking or two-photon sideband interference experiments. Comparison with reported time-delay measurements in Ne and Ar at a few selected photon energies is made. Systematic mapping of time delay across a wide range of photon energies in several atomic targets allows to highlight important aspects of fundamental atomic physics that can be probed by attosecond-time-delay measurements.", author = "Kheifets, \{A. S.\}", year = "2013", month = jun, day = "6", doi = "10.1103/PhysRevA.87.063404", language = "English", volume = "87", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Measurement of laser intensities approaching 1015 W/cm2 with an accuracy of 1% @article{cce9e70ad0a4410d9e7b7eb72b58f746, title = "Measurement of laser intensities approaching 1015 W/cm2 with an accuracy of 1\%", abstract = "Accurate knowledge of the intensity of focused ultrashort laser pulses is crucial to the correct interpretation of experimental results in strong-field physics. We have developed a technique to measure laser intensities approaching 1015W/cm2 with an accuracy of 1\%. This accuracy is achieved by comparing experimental photoelectron yields from atomic hydrogen with predictions from exact numerical solutions of the three-dimensional time-dependent Schr{\"o}dinger equation. Our method can be extended to relativistic intensities and to the use of other atomic species.", author = "Pullen, \{M. G.\} and Wallace, \{W. C.\} and Laban, \{D. E.\} and Palmer, \{A. J.\} and Hanne, \{G. F.\} and Grum-Grzhimailo, \{A. N.\} and K. Bartschat and I. Ivanov and A. Kheifets and D. Wells and Quiney, \{H. M.\} and Tong, \{X. M.\} and Litvinyuk, \{I. V.\} and Sang, \{R. T.\} and D. Kielpinski", year = "2013", month = may, day = "22", doi = "10.1103/PhysRevA.87.053411", language = "English", volume = "87", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Time delay in atomic photoionization with circularly polarized light @article{4225164e500c41a69d281a8a51e35d9f, title = "Time delay in atomic photoionization with circularly polarized light", abstract = "We study time delay in atomic photoionization by circularly polarized light. By considering the Li atom in an excited 2p state, we demonstrate a strong time-delay asymmetry between the photoemission of the target electrons that are co- and counter-rotating with the electromagnetic field in the polarization plane. In addition, we observe the time-delay sensitivity to the polar angle of the photoelectron emission in the polarization plane. This modulation depends on the shape and duration of the electromagnetic pulse.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2013", month = mar, day = "7", doi = "10.1103/PhysRevA.87.033407", language = "English", volume = "87", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "3", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Signature of two-electron interference in angular resolved double photoionization of Mg @article{6826ff7fcf924e439907dd6411d9ed27, title = "Signature of two-electron interference in angular resolved double photoionization of Mg", abstract = "The double photoionization of Mg has been studied experimentally and theoretically in a kinematic where the two photoelectrons equally share the excess energy. The observation of a symmetrized gerade amplitude, which strongly deviates from the Gaussian ansatz, is explained by a two-electron interference predicted theoretically, but never before observed experimentally. Similar to the Cooper minima in the single photoionization cross section, the effect finds its origin in the radial extent and oscillation of the target wave function.", author = "E. Sokell and P. Bolognesi and A. Kheifets and I. Bray and S. Safgren and L. Avaldi", year = "2013", month = feb, day = "20", doi = "10.1103/PhysRevLett.110.083001", language = "English", volume = "110", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "8", } . Physical Review Letters.

Two-photon double ionization of the H2 molecule @article{249ce0dab7fb48f4b5bfbb0bcd5d7c46, title = "Two-photon double ionization of the H2 molecule: Cross sections and amplitude analysis", abstract = "We perform time-dependent calculations of triply differential cross sections (TDCS) of two-photon double-electron ionization of the aligned H 2 molecule. Our TDCS results for equal energy sharing between photoelectrons agree quite well with a recent time-dependent calculation by Guan who employed a slightly different numerical technique. We supplement these studies by calculating TDCS at an unequal energy sharing and by generating symmetrized ionization amplitudes.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2013", month = feb, day = "19", doi = "10.1103/PhysRevA.87.023414", language = "English", volume = "87", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

C. Simenel, M. Dasgupta, D. J. Hinde, A. Kheifets, A. Wakhle(2013). Probing quantum many-body dynamics in nuclear systems . EPJ Web of Conferences. 63. EDP Sciences

Schoeffler, M. S., Stuck, C., Waitz, M., Trinter, F., Jahnke, T., Lenz, U., Jones, M., Belkacem, A., Landers, A. L., Pindzola, M. S., et al.(2013). Ejection of Quasi-Free-Electron Pairs from the Helium-Atom Ground State by Single-Photon Absorption . Physical Review Letters. 111. (1).

A. S. Kheifets (2013). Time delay in valence-shell photoionization of noble-gas atoms . Physical Review A.

Ivanov, I. A., Kheifets, A. S.(2013). Two-photon double ionization of the H-2 molecule: Cross sections and amplitude analysis . Physical Review a. 87. (2).

Ivanov, I. A., Kheifets, A. S.(2013). Extraction of the attosecond time delay in atomic photoionization using the soft-photon approximation . Physical Review a. 87. (6).

Ivanov, I. A., Kheifets, A. S. (2013). Two-photon double ionization of the H₂ molecule: Cross sections and amplitude analysis . Physical Review A.

Kheifets, A. S.(2013). Time delay in valence-shell photoionization of noble-gas atoms . Physical Review a. 87. (6).

Schoeffler, M. S., Stuck, C., Waitz, M., Trinter, F., Jahnke, T., Lenz, U., Jones, M., Belkacem, A., Landers, A. L., Pindzola, M. S., et al. (2013). Ejection of Quasi-Free-Electron Pairs from the Helium-Atom Ground State by Single-Photon Absorption . Physical Review Letters.

Pullen, M. G., Wallace, W. C., Laban, D. E., Palmer, A. J., Hanne, G. F., Grum-Grzhimailo, A. N., Bartschat, K., Ivanov, I., Kheifets, A., Wells, D., et al.(2013). Measurement of laser intensities approaching 10(15) W/cm(2) with an accuracy of 1% . Physical Review a. 87. (5).

Ivanov, I. A., Kheifets, A. S.(2013). Time delay in atomic photoionization with circularly polarized light . Physical Review a. 87. (3).

Ivanov, I. A., Kheifets, A. S. (2013). Extraction of the attosecond time delay in atomic photoionization using the soft-photon approximation . Physical Review A.

Sokell, E., Bolognesi, P., Kheifets, A., Bray, I., Safgren, S., Avaldi, L. (2013). Signature of Two-Electron Interference in Angular Resolved Double Photoionization of Mg . Physical Review Letters.

Pullen, M. G., Wallace, W. C., Laban, D. E., Palmer, A. J., Hanne, G. F., Grum-Grzhimailo, A. N., Bartschat, K., Ivanov, I., Kheifets, A., Wells, D., et al. (2013). Measurement of laser intensities approaching 10<SUP>15</SUP> W/cm<SUP>2</SUP> with an accuracy of 1% . Physical Review A.

Sokell, E., Bolognesi, P., Kheifets, A., Bray, I., Safgren, S., Avaldi, L.(2013). Signature of Two-Electron Interference in Angular Resolved Double Photoionization of Mg . Physical Review Letters. 110. (8).

Ivanov, I. A., Kheifets, A. S. (2013). Time delay in atomic photoionization with circularly polarized light . Physical Review A.

Attosecond time-delay spectroscopy of the hydrogen molecule @article{1c0e505ee7684900b83f622b35394a89, title = "Attosecond time-delay spectroscopy of the hydrogen molecule", abstract = "We apply the concept of photoemission time delay to the process of single-photon one-electron ionization of the H2 molecule. We demonstrate that, by resolving the photoelectron detection in time on the attosecond scale, one can extract differential photoionization cross sections for particular field and molecule orientations from the measurement on a randomly oriented molecule", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and Serov, \{Vladislav V.\}", year = "2012", month = dec, day = "27", doi = "10.1103/PhysRevA.86.063422", language = "English", volume = "86", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Electron- and photon-impact atomic ionisation @article{b9fd0cc2a5664d3999614f062c88f674, title = "Electron- and photon-impact atomic ionisation", abstract = "The past decade has seen extraordinary theoretical progress in the field of fully kinematically resolved atomic electron-impact ionisation, and its closely related field of double photoionisation. These processes were challenging to calculate due to formal and computational difficulties associated with break-up problems involving the long-range Coulomb potential. Presently, however, these processes can be calculated accurately for simple targets such as atomic hydrogen and helium, irrespective of the kinematics considered or the geometry of detectors. We report on the computational progress, and how it has resulted in a deeper understanding of the formalism of Coulomb few-body problems.", keywords = "Double photoionisation, Electron-impact ionisation", author = "I. Bray and Fursa, \{D. V.\} and Kadyrov, \{A. S.\} and Stelbovics, \{A. T.\} and Kheifets, \{A. S.\} and Mukhamedzhanov, \{A. M.\}", year = "2012", month = nov, doi = "10.1016/j.physrep.2012.07.002", language = "English", volume = "520", pages = "135--174", journal = "Physics Reports", issn = "0370-1573", publisher = "Elsevier B.V.", number = "3", } . Physics Reports.

Single-photon double ionization of H 2 away from equilibrium @article{8756829065ef405e9438f22bb09c54ff, title = "Single-photon double ionization of H 2 away from equilibrium: A showcase of two-center electron interference", abstract = "We demonstrate the effect of two-center interference on single-photon double ionization [double photoionization (DPI)] of the aligned H 2 molecule when it shrinks or expands from the equilibrium internuclear distance. This interference affects the first stage of the DPI process in which the primary photoelectron is ejected predominantly along the polarization axis of light and its geometrical interference factor is most sensitive to the internuclear distance in the parallel (Σ) orientation of the internuclear and polarization axes. This effect is responsible for strong modification of the DPI amplitude in the parallel orientation while the corresponding amplitude for the perpendicular (Π) orientation is rather insensitive to the internuclear distance. The combination of these two factors explains the profound kinetic energy release effect on the fully differential cross sections of DPI of H 2.", author = "Serov, \{Vladislav V.\} and Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2012", month = aug, day = "15", doi = "10.1103/PhysRevA.86.025401", language = "English", volume = "86", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Photoemission-time-delay measurements and calculations close to the 3s-ionization-cross-section minimum in Ar @article{7571d1969c764020bd662d1d428c863c, title = "Photoemission-time-delay measurements and calculations close to the 3s-ionization-cross-section minimum in Ar", abstract = "We present experimental measurements and theoretical calculations of photoionization time delays from the 3s and 3p shells in Ar in the photon energy range of 32-42 eV. The experimental measurements are performed by interferometry using attosecond pulse trains and the infrared laser used for their generation. The theoretical approach includes intershell correlation effects between the 3s and 3p shells within the framework of the random-phase approximation with exchange. The connection between single-photon ionization and the two-color two-photon ionization process used in the measurement is established using the recently developed asymptotic approximation for the complex transition amplitudes of laser-assisted photoionization. We compare and discuss the theoretical and experimental results, especially in the region where strong intershell correlations in the 3s→kp channel lead to an induced {"}Cooper{"} minimum in the 3s ionization cross section.", author = "D. Gu{\'e}not and K. Kl{\"u}nder and Arnold, \{C. L.\} and D. Kroon and Dahlstr{\"o}m, \{J. M.\} and M. Miranda and T. Fordell and M. Gisselbrecht and P. Johnsson and J. Mauritsson and E. Lindroth and A. Maquet and R. Ta{\"i}eb and A. L'Huillier and Kheifets, \{A. S.\}", year = "2012", month = may, day = "31", doi = "10.1103/PhysRevA.85.053424", language = "English", volume = "85", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Locating the origin of photoelectrons in atomic photoionizaton @article{717d14a8fbcc438a9983c32164f7fe29, title = "Locating the origin of photoelectrons in atomic photoionizaton", abstract = "We perform a time-delay analysis of the strong field ionization of atomic hydrogen in the tunneling regime. We obtain values for the time delay by solving the time-dependent Schr{\"o}dinger equation, and use these values as parameters to define the corresponding classical trajectories. We demonstrate that almost all of these trajectories tend to cluster together to a few starting points. The identification of these starting points and their corresponding starting times allows one to answer the question as to when and where the atomic photoionization process actually begins.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2012", month = feb, day = "10", doi = "10.1103/PhysRevA.85.021401", language = "English", volume = "85", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Time-dependent calculations of double photoionization of the aligned H 2 molecule @article{e168647c56e244cdbb138608f94ddde7, title = "Time-dependent calculations of double photoionization of the aligned H 2 molecule", abstract = "We perform time-dependent calculations of single-photon two-electron ionization of the aligned H 2 molecule by an xuv pulse. Solution of the time-dependent Schr{\"o}dinger equation is sought in spherical coordinates on a radial grid by time propagation using the Arnoldi-Lanczos method. From these calculations, we derive the total integrated as well as fully differential ionization cross sections for equal energy sharing and various orientations of the internuclear axis relative to the polarization vector of light. Satisfactory agreement with available literature data validates the present theoretical model. We supplement our numerical computations with an amplitude analysis of differential cross sections using the atomiclike formalism of Feagin. This analysis provides some additional insight into mechanisms of double photoionization of the aligned H 2 molecule.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2012", month = jan, day = "10", doi = "10.1103/PhysRevA.85.013406", language = "English", volume = "85", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "1", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Guenot, D., Klunder, K., Arnold, C. L., Kroon, D., Dahlstrom, J. M., Miranda, M., Fordell, T., Gisselbrecht, M., Johnsson, P., Mauritsson, J., et al.(2012). Photoemission-time-delay measurements and calculations close to the 3s-ionization-cross-section minimum in Ar . Physical Review a. 85. (5).

A. S. Kheifets, I. A. Ivanov, Igor Bray(2012). Atomic photoionization . Journal of Physics: Conference Series. 388. (PART 3). IOP Publishing Ltd.

Serov, Vladislav V., Ivanov, I. A., Kheifets, A. S. (2012). Single-photon double ionization of H₂ away from equilibrium: A showcase of two-center electron interference . Physical Review A.

I. Bray, D.V. Fursa, A.S. Kadyrov, A.T. Stelbovics, A.S. Kheifets, A.M. Mukhamedzhanov (2012). Electron- and photon-impact atomic ionisation . Physical Review Letters.

A. S. Kheifets, D. V. Fursa, Igor Bray, J. Colgan, M. S. Pindzola(2012). Differential cross-sections for the double photoionization of lithium . Journal of Physics: Conference Series. 388. (PART 2). IOP Publishing Ltd.

Ivanov, I. A., Kheifets, A. S., Serov, Vladislav V. (2012). Attosecond time-delay spectroscopy of the hydrogen molecule . Physical Review A.

Bray, I., Fursa, D. V., Kadyrov, A. S., Stelbovics, A. T., Kheifets, A. S., Mukhamedzhanov, A. M.(2012). Electron- and photon-impact atomic ionisation . Physics Reports-Review Section of Physics Letters. 520. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 135-174.

Ivanov, I. A., Kheifets, A. S. (2012). Locating the origin of photoelectrons in atomic photoionizaton . Physical Review A.

Ivanov, I. A., Kheifets, A. S.(2012). Time-dependent calculations of double photoionization of the aligned H(2) molecule . Physical Review a. 85. (1).

Serov, Vladislav V., Ivanov, I. A., Kheifets, A. S.(2012). Single-photon double ionization of H-2 away from equilibrium: A showcase of two-center electron interference . Physical Review a. 86. (2).

Ivanov, I. A., Kheifets, A. S., Serov, Vladislav V.(2012). Attosecond time-delay spectroscopy of the hydrogen molecule . Physical Review a. 86. (6).

I. A. Ivanov, A. S. Kheifets(2012). Complete characterization of the process of single-photon two-electron ionization of helium . Journal of Physics: Conference Series. 388. (PART 2). IOP Publishing Ltd.

Ivanov, I. A., Kheifets, A. S.(2012). Locating the origin of photoelectrons in atomic photoionizaton . Physical Review a. 85. (2).

W. C. Wallace, M. G. Pullen, D. E. Laban, A. J. Palmer, G. F. Hanne, A. N. Grum-Grzhimailo, B. Abeln, K. Bartschat, D. Weflen, I. Ivanov, et al.(2012). Above-threshold ionization in atomic hydrogen using intense, few-cycle laser pulses . Journal of Physics: Conference Series. 388. (PART 3). IOP Publishing Ltd.

Guenot, D., Klunder, K., Arnold, C. L., Kroon, D., Dahlstrom, J. M., Miranda, M., Fordell, T., Gisselbrecht, M., Johnsson, P., Mauritsson, J., et al. (2012). Photoemission-time-delay measurements and calculations close to the 3<i>s</i>-ionization-cross-section minimum in Ar . Physical Review A.

Ivanov, I. A., Kheifets, A. S. (2012). Time-dependent calculations of double photoionization of the aligned H₂ molecule . Physical Review A.

Experimental ionization of atomic hydrogen with few-cycle pulses @article{9afd76651b34482aa40dac1f27f2f26a, title = "Experimental ionization of atomic hydrogen with few-cycle pulses", abstract = "We present experimental data on strong-field ionization of atomic hydrogen by few-cycle laser pulses. We obtain quantitative agreement at the 10\% level between the data and an ab initio simulation over a wide range of laser intensities and electron energies.", author = "Pullen, \{M. G.\} and Wallace, \{W. C.\} and Laban, \{D. E.\} and Palmer, \{A. J.\} and Hanne, \{G. F.\} and Grum-Grzhimailo, \{A. N.\} and B. Abeln and K. Bartschat and D. Weflen and I. Ivanov and A. Kheifets and Quiney, \{H. M.\} and Litvinyuk, \{I. V.\} and Sang, \{R. T.\} and D. Kielpinski", year = "2011", month = sep, day = "15", doi = "10.1364/OL.36.003660", language = "English", volume = "36", pages = "3660--3662", journal = "Optics Letters", issn = "0146-9592", publisher = "Optica Publishing Group", number = "18", } . Optics Letters.

Complete characterization of double photoionization processes @article{36d26ac87e17430097fcf47d8f7a1b0c, title = "Complete characterization of double photoionization processes", abstract = "We analyze correlated photoelectron spectra of single-photon two-electron ionization [double photoionization (DPI)] of helium to reconstruct the phase of the spectral amplitude of this process. The phase can be reconstructed reliably in a wide range of photoelectron momenta, thus allowing one to retrieve information about the wave function of the DPI process and its temporal evolution. Our simulation indicates that the proposed phase reconstruction technique can be applied in experiment to trace dynamics of the DPI process with attosecond precision.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2011", month = jun, day = "16", doi = "10.1103/PhysRevA.83.063411", language = "English", volume = "83", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Timing analysis of two-electron photoemission @article{2956460ce4bf4c24a91ba7966ef749cd, title = "Timing analysis of two-electron photoemission", abstract = "We predict a significant delay of two-electron photoemission from the helium atom after absorption of an attosecond XUV pulse. We establish this delay by solving the time-dependent Schr{\"o}dinger equation and by subsequently tracing the field-free evolution of the two-electron wave packet. This delay can also be related to the energy derivative of the phase of the complex double-photoionization (DPI) amplitude which we evaluate by using the convergent close-coupling method. Our observations indicate that future attosecond time delay measurements on DPI of He can provide information on the absolute quantum phase and elucidate various mechanisms of this strongly correlated ionization process.", author = "Kheifets, \{A. S.\} and Ivanov, \{I. A.\} and Igor Bray", year = "2011", month = may, day = "28", doi = "10.1088/0953-4075/44/10/101003", language = "English", volume = "44", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "10", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Strong-field ionization of lithium @article{8b26d7a1ed06435f85e13289aee9d39d, title = "Strong-field ionization of lithium", abstract = "We report photoelectron energy spectra, momentum, and angular distributions for the strong-field single ionization of lithium by 30-fs laser pulses. For peak intensities between 1011 and 1014 W/cm2 at a central wavelength of 785 nm, the classical over-the-barrier intensity was reached well inside the multiphoton regime. The complete vector momenta of the ionization fragments were recorded by a reaction microscope with a magneto-optically trapped target (MOTREMI). On the theoretical side, the time-dependent Schr{\"o}dinger equation was solved by two independent methods seeking the solution directly on a radial grid. Distinct differences between the results of both calculations and also in comparison with experiment point to a high sensitivity of this reaction with respect to small details, particularly in the description of the Li+ core.", author = "Michael Schuricke and Ganjun Zhu and Jochen Steinmann and Konstantinos Simeonidis and Igor Ivanov and Anatoli Kheifets and Grum-Grzhimailo, \{Alexei N.\} and Klaus Bartschat and Alexander Dorn and Joachim Ullrich", year = "2011", month = feb, day = "16", doi = "10.1103/PhysRevA.83.023413", language = "English", volume = "83", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

On the account of final state correlation in double ionization processes @article{f950a8d6beca4f88ae0d60b859e1bd73, title = "On the account of final state correlation in double ionization processes", abstract = "We discuss the use of uncorrelated final state wave functions in calculations of double ionization processes. We show that in some physical situations such a simplified treatment can provide meaningful results. In particular, the prevalence of back-to-back emission in two-photon double ionization and even energy sharing between the photoelectrons make it possible to use uncorrelated final state wave functions for total integrated cross-section calculations.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\} and J. Dubau", year = "2011", month = feb, doi = "10.1140/epjd/e2011-10496-6", language = "English", volume = "61", pages = "563--569", journal = "European Physical Journal D", issn = "1434-6060", publisher = "Springer Science+Business Media B.V.", number = "3", } . European Physical Journal D.

Interference effects in L-shell atomic double photoionization @article{777d801157b04fff892b4f9b7dab1f79, title = "Interference effects in L-shell atomic double photoionization", abstract = "Angular correlation pattern in two-electron continuum is very similar in double photoionization (DPI) of a neutral atom γ + A → A2+ + 2e- and electron-impact ionization of the corresponding singly charged ion e- + A+ → A2+ + 2e -. This allows us to identify and interpret interference effects in DPI of various L-shell atomic targets such as the metastable He * 1s 2s 1S and the ground state Li 1s22s and Be 1s22s2.", author = "Kheifets, \{A. S.\} and I. Bray and J. Colgan and Pindzola, \{M. S.\}", year = "2011", month = jan, day = "14", doi = "10.1088/0953-4075/44/1/011002", language = "English", volume = "44", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "1", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Ivanov, I. A., Kheifets, A. S. (2011). Complete characterization of double photoionization processes . Physical Review A.

Ivanov, IA, Kheifets, AS, Dubau, J(2011). On the account of final state correlation in double ionization processes . European Physical Journal D. 61. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 563-569.

Ivanov, I. A., Kheifets, A. S.(2011). Complete characterization of double photoionization processes . Physical Review a. 83. (6).

Ivanov, I. A., Kheifets, A. S., Dubau, J. (2011). On the account of final state correlation in double ionization processes . The European Physical Journal D.

Kheifets, AS, Ivanov, IA, Bray, I(2011). Timing analysis of two-electron photoemission . Journal of Physics B-Atomic Molecular and Optical Physics. 44. (10).

Schuricke, M, Zhu, GJ, Steinmann, J, Simeonidis, K, Ivanov, I, Kheifets, A, Grum-Grzhimailo, AN, Bartschat, K, Dorn, A, Ullrich, J(2011). Strong-field ionization of lithium . Physical Review a. 83. (2).

Kheifets, Anatoli, Schuricke, Michael, Zhu, Ganjun, Steinmann, Jochen, Simeonidis, Konstantinos, Ivanov, Igor, Grum-Grzhimailo, Alexei N., Bartschat, Klaus, Dorn, Alexander, Ullrich, Joachim (2011). Strong-field ionization of lithium . Physical Review A.

Kheifets, AS, Bray, I, Colgan, J, Pindzola, MS(2011). Interference effects in L-shell atomic double photoionization . Journal of Physics B-Atomic Molecular and Optical Physics. 44. (1).

Kheifets, A. S., Ivanov, I. A., Bray, Igor (2011). Timing analysis of two-electron photoemission . Journal of Physics B: Atomic, Molecular and Optical Physics.

A S Kheifets, I Bray, J Colgan, M S Pindzola (2011). Interference effects in L-shell atomic double photoionization . Journal of Physics B: Atomic, Molecular and Optical Physics.

Pullen, M. G., Wallace, W. C., Laban, D. E., Palmer, A. J., Hanne, G. F., Grum-Grzhimailo, A. N., Abeln, B., Bartschat, K., Weflen, D., Ivanov, I., et al. (2011). Experimental ionization of atomic hydrogen with few-cycle pulses . Optics Letters.

Pullen, M. G., Wallace, W. C., Laban, D. E., Palmer, A. J., Hanne, G. F., Grum-Grzhimailo, A. N., Abeln, B., Bartschat, K., Weflen, D., Ivanov, I., et al.(2011). Experimental ionization of atomic hydrogen with few-cycle pulses . Optics Letters. 36. (18). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3660-3662.

Delay in atomic photoionization @article{b217e741d5a640e28a99142fdf8d85fd, title = "Delay in atomic photoionization", abstract = "We analyze the time delay between emission of photoelectrons from the outer valence ns and np subshells in noble gas atoms following absorption of an attosecond extreme ultraviolet pulse. Various processes such as elastic scattering of the photoelectron on the parent ion and many-electron correlation affect the apparent {"}time zero{"} when the photoelectron leaves the atom. This qualitatively explains the time delay between photoemission from the 2s and 2p subshells of Ne as determined experimentally by attosecond streaking. However, with our extensive numerical modeling, we were only able to account for less than half of the measured time delay of 21± as. We argue that the extreme ultraviolet pulse alone cannot produce such a large time delay and it is the streaking IR field that is most likely responsible for this effect.", author = "Kheifets, \{A. S.\} and Ivanov, \{I. A.\}", year = "2010", month = dec, day = "1", doi = "10.1103/PhysRevLett.105.233002", language = "English", volume = "105", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "23", } . Physical Review Letters.

Benchmark calculations for electron impact ionization and ionization-excitation of magnesium @article{3bb566ab868c4d07afce91e461fab202, title = "Benchmark calculations for electron impact ionization and ionization-excitation of magnesium", abstract = "We compare results of various numerical calculations for electron impact ionization of the ground state Mg (3s2) leading to the final ionic ground state Mg+(3s) or the excited ionic states Mg+(3p, 4s, 3d). Although our numerical results exhibit some model dependence, especially for small values of the triple-differential cross section, we cannot resolve the significant differences between experiment and theory reported by Bolognesi et al (2008 J. Phys. B: At. Mol. Opt. Phys. 41 065203). Extensive theoretical modelling allows us to identify possible sources of this strong disagreement and to suggest future investigations.", author = "Klaus Bartschat and Kheifets, \{Anatoli S.\} and Fursa, \{Dmitry V.\} and Igor Bray", year = "2010", month = aug, day = "28", doi = "10.1088/0953-4075/43/16/165205", language = "English", volume = "43", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "16", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Differential cross sections of double photoionization of lithium @article{f4175cd255214a4ca0054450ad27a575, title = "Differential cross sections of double photoionization of lithium", abstract = "We extend our previous application of the convergent close-coupling (CCC) and time-dependent close-coupling (TDCC) methods to describe energy and angular resolved double photoionization (DPI) of lithium at arbitrary energy sharing. By doing so, we are able to evaluate the recoil ion momentum distribution of DPI of Li and make a comparison with recent measurements of Zhu [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.103.103008 103, 103008 (2009)].", author = "Kheifets, \{A. S.\} and Fursa, \{D. V.\} and I. Bray and J. Colgan and Pindzola, \{M. S.\}", year = "2010", month = aug, day = "3", doi = "10.1103/PhysRevA.82.023403", language = "English", volume = "82", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Spin effects in double photoionization of lithium @article{e4209016d9064940b3a2b48b6fa6f8ec, title = "Spin effects in double photoionization of lithium", abstract = "We apply the nonperturbative convergent close-coupling (CCC) and time-dependent close coupling (TDCC) formalisms to calculate fully differential energy and angular resolved cross sections of double photoionization (DPI) of lithium. The equal energy sharing case is considered in which dynamics of the DPI process can be adequately described by two symmetrized singlet and triplet amplitudes. The angular width of these amplitudes serves as a measure of the strength of the angular correlation between the two ejected electrons. This width is interpreted in terms of the spin of the photoelectron pair.", author = "Kheifets, \{A. S.\} and Fursa, \{D. V.\} and Hines, \{C. W.\} and I. Bray and J. Colgan and Pindzola, \{M. S.\}", year = "2010", month = feb, day = "22", doi = "10.1103/PhysRevA.81.023418", language = "English", volume = "81", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

I. Bray, D. V. Fursa, A. S. Kadyrov, A. S. Kheifets, T. Lepage, A. T. Stelbovics(2010). Spin-resolved electron-impact ionisation of atoms . Journal of Physics: Conference Series. 212. IOP Publishing Ltd.

Kheifets, AS, Ivanov, IA(2010). Delay in Atomic Photoionization . Physical Review Letters. 105. (23).

Bartschat, K, Kheifets, AS, Fursa, DV, Bray, I(2010). Benchmark calculations for electron impact ionization and ionization-excitation of magnesium . Journal of Physics B-Atomic Molecular and Optical Physics. 43. (16).

A. S. Kheifets, D. V. Fursa, C. W. Hines, I. Bray, J. Colgan, M. S. Pindzola (2010). Spin effects in double photoionization of lithium . Physical Review A.

Klaus Bartschat, Anatoli S Kheifets, Dmitry V Fursa, Igor Bray (2010). Benchmark calculations for electron impact ionization and ionization-excitation of magnesium . Journal of Physics B: Atomic, Molecular and Optical Physics.

A. S. Kheifets, D. V. Fursa, I. Bray, J. Colgan, M. S. Pindzola (2010). Differential cross sections of double photoionization of lithium . Physical Review A.

Kheifets, AS, Fursa, DV, Bray, I, Colgan, J, Pindzola, MS(2010). Differential cross sections of double photoionization of lithium . Physical Review a. 82. (2).

J. Hoszowska, S. Kheifets, Dousse J-Cl Dousse, I. Bray, W. Cao, K. Fennane, Y. Kayser, M. Kačvič, J. Szlachetko, M. Szlachetko(2010). Single-photon double K-shell ionization of low-Z atoms . Journal of Physics: Conference Series. 212. IOP Publishing Ltd.

KHEIFETS, AS, FURSA, DV, HINES, CW, BRAY, I, COLGAN, J, PINDZOLA, MS(2010). Spin effects in double photoionization of lithium . PHYSICAL REVIEW A. 81. (2).

Kheifets, A. S., Ivanov, I. A. (2010). Delay in Atomic Photoionization . Physical Review Letters.

I. A. Ivanov, A. S. Kheifets(2010). Atomic systems with one and two active electrons in electromagnetic fields . Journal of Physics: Conference Series. 212. IOP Publishing Ltd.

Above-threshold-ionization structures in photoelectron momentum distributions for single ionization of He by a strong electromagnetic field @article{f072504e173a4bc9a7e2934ed1d77a3f, title = "Above-threshold-ionization structures in photoelectron momentum distributions for single ionization of He by a strong electromagnetic field", abstract = "Our numerical calculations support a recently advanced hypothesis that an individual photon absorption is still a valid concept in the tunneling regime of atomic ionization in a strong electromagnetic field. We observe characteristic structures in the photoelectron momentum distribution resulting from single ionization of the helium atom in the tunneling regime which are normally associated with above threshold ionization (ATI). The nodal structure of these ATI-like rings varies with the photon energy which can be attributed to altering parity of the photon numbers producing the corresponding rings.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2009", month = dec, day = "8", doi = "10.1103/PhysRevA.80.063418", language = "English", volume = "80", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Two-electron photoionization of ground-state lithium @article{ce5d0a034da6428ab862b91aba9e9d90, title = "Two-electron photoionization of ground-state lithium", abstract = "We apply the convergent close-coupling (CCC) formalism to single-photon two-electron ionization of the lithium atom in its ground state. We treat this reaction as single-electron photon absorption followed by inelastic scattering of the photoelectron on a heliumlike Li+ ion. The latter scattering process can be described accurately within the CCC formalism. We obtain integrated cross sections of single photoionization leading to the ground and various excited states of the Li+ ion as well as double photoionization extending continuously from the threshold to the asymptotic limit of infinite photon energy. Comparison with available experimental and theoretical data validates the CCC model.", author = "Kheifets, \{A. S.\} and Fursa, \{D. V.\} and I. Bray", year = "2009", month = dec, day = "7", doi = "10.1103/PhysRevA.80.063413", language = "English", volume = "80", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Tailoring the waveforms to extend the high-order harmonic generation cutoff @article{4cac7e60bbbd4c3ca7b708042f476165, title = "Tailoring the waveforms to extend the high-order harmonic generation cutoff", abstract = "Increase in the cutoff value in the high-order harmonics generation process is demonstrated for a special case of the driving field composed of several harmonics of a given frequency. It is shown that a moderate, of the order of 20\%, increase in the cutoff value can be achieved. This result possibly constitutes an upper limit for the increase in the cutoff value, attainable for a class of the waveforms considered in the paper.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2009", month = aug, day = "14", doi = "10.1103/PhysRevA.80.023809", language = "English", volume = "80", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

A S Kheifets(2009). Photoelectron angular correlation pattern in sequential two-photon double ionization of neon . Journal of Physics B: Atomic, Molecular and Optical Physics. 42. (13). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 134016. {IOP} Publishing

Harmonic generation for atoms in fields of varying ellipticity @article{9a2d0e34acc9484dafd60045f07477b2, title = "Harmonic generation for atoms in fields of varying ellipticity: Single-active-electron model with Hartree-Fock potential", abstract = "We propose a theoretical procedure for calculating harmonics yield from atoms based on the solution of a three-dimensional time-dependent Schr{\"o}dinger equation. The atomic system is described by means of the Hartree-Fock potential, including the exchange interaction. We present results for the harmonics generation in lithium and rubidium in situation when ellipticity of the driving laser changes with time. These results show that harmonics are formed primarily at the intervals of time when the driving laser field has nearly zero ellipticity. This can be used for generation of short (hundreds of attoseconds) bursts of radiation.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2009", month = may, day = "1", doi = "10.1103/PhysRevA.79.053827", language = "English", volume = "79", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

K -shell double photoionization of Be, Mg, and Ca @article{32dbabf346094f3c9205b735a41c7f05, title = "K -shell double photoionization of Be, Mg, and Ca", abstract = "We perform convergent close-coupling calculations of double photoionization (DPI) of the K -shell of alkaline-earth metal atoms (Be, Mg, and Ca) from the threshold to the nonrelativistic limit of infinite photon energy. Theoretical double-to-single photoionization cross-section ratios for Mg and Ca are compared with experimental values derived from high-resolution x-ray spectra following the radiative decay of the K -shell double vacancy. We investigate the role of many-electron correlations in the ground and doubly-ionized final states played in the DPI process. Universal scaling of DPI cross section with an effective nuclear charge is examined in neutral atoms in comparison with corresponding heliumlike ions.", author = "Kheifets, \{A. S.\} and Igor Bray and J. Hoszowska", year = "2009", month = apr, day = "1", doi = "10.1103/PhysRevA.79.042504", language = "English", volume = "79", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "4", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Physical mechanisms and scaling laws of K-shell double photoionization @article{9bcc05d923094c13856cacb42d77feb0, title = "Physical mechanisms and scaling laws of K-shell double photoionization", abstract = "We report on the photon energy dependence of the K-shell double photoionization (DPI) of Mg, Al, and Si. The DPI cross sections were derived from high-resolution measurements of x-ray spectra following the radiative decay of the K-shell double vacancy states. Our data evince the relative importance of the final-state electron-electron interaction to the DPI. By comparing the double-to-single K-shell photoionization cross-section ratios for neutral atoms with convergent close-coupling calculations for He-like ions, the effect of outer shell electrons on the K-shell DPI process is assessed. Universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms is revealed.", author = "J. Hoszowska and Kheifets, \{A. K.\} and Dousse, \{J. Cl\} and M. Berset and I. Bray and W. Cao and K. Fennane and Y. Kayser and M. Kav{\v c}i{\v c} and J. Szlachetko and M. Szlachetko", year = "2009", month = feb, day = "20", doi = "10.1103/PhysRevLett.102.073006", language = "English", volume = "102", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "7", } . Physical Review Letters.

Angular anisotropy parameters for sequential two-photon double ionization of helium @article{53023c2a96f6435f92f96827822ab4e4, title = "Angular anisotropy parameters for sequential two-photon double ionization of helium", abstract = "We evaluate photoelectron angular anisotropy β parameters for the process of sequential two-photon double electron ionization of helium within the lowest-order time-independent perturbation theory. Our results indicate that for photoelectron energies outside the interval (Eslow, Efast), where Eslow =ω- V He+ and Efast =ω- VHe, there is a considerable deviation from the dipole angular distribution, thus indicating the effect of electron correlation.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2009", month = feb, day = "2", doi = "10.1103/PhysRevA.79.023409", language = "English", volume = "79", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Fully differential cross-section measurements for electron-impact ionization of neon and xenon @article{a28cbc2fc47d48d58d6e117c21ec027c, title = "Fully differential cross-section measurements for electron-impact ionization of neon and xenon", abstract = "We present a combined experimental and theoretical investigation of the fully differential cross section for electron-impact ionization of neon and xenon. The experiments were performed under coplanar asymmetric kinematics, at intermediate incident electron energies, and for a range of scattered electron detection angles. The experimental results are compared with three calculations: a convergent close-coupling calculation, a distorted-wave Born approximation (DWBA) calculation with inclusion of the Gamow factor, and a hybrid DWBA+R -matrix calculation. The comparison between the experimental and theoretical results highlights the importance of the description of postcollision interaction, and the results exhibit interesting orbital-dependent differences.", author = "Stevenson, \{M. A.\} and Hargreaves, \{L. R.\} and B. Lohmann and I. Bray and Fursa, \{D. V.\} and K. Bartschat and A. Kheifets", year = "2009", month = jan, day = "5", doi = "10.1103/PhysRevA.79.012709", language = "English", volume = "79", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "1", } . Physical Review A - Atomic, Molecular, and Optical Physics.

IVANOV, IA, KHEIFETS, AS(2009). Above-threshold-ionization structures in photoelectron momentum distributions for single ionization of He by a strong electromagnetic field . PHYSICAL REVIEW A. 80. (6).

IVANOV, IA, KHEIFETS, AS(2009). Harmonic generation for atoms in fields of varying ellipticity: Single-active-electron model with Hartree-Fock potential . PHYSICAL REVIEW A. 79. (5).

KHEIFETS, AS, BRAY, I, HOSZOWSKA, J(2009). K-shell double photoionization of Be, Mg, and Ca . PHYSICAL REVIEW A. 79. (4).

HOSZOWSKA, J, KHEIFETS, AK, DOUSSE, JC, BERSET, M, BRAY, I, CAO, W, FENNANE, K, KAYSER, Y, KAVCIC, M, SZLACHETKO, J, et al.(2009). Physical Mechanisms and Scaling Laws of K-Shell Double Photoionization . PHYSICAL REVIEW LETTERS. 102. (7).

I A Ivanov, A S Kheifets (2009). Calculation of HHG spectra in complex atoms . Journal of Physics B: Atomic, Molecular and Optical Physics.

I. A. Ivanov, A. S. Kheifets (2009). Angular anisotropy parameters for sequential two-photon double ionization of helium . Physical Review A.

Kheifets, A. S. (2009). Photoelectron angular correlation pattern in sequential two-photon double ionization of neon . Journal of Physics B: Atomic, Molecular and Optical Physics.

Joanna Hoszowska, A. S. Kheifets, M. Berset, I. Bray, W. Cao, J. C.l. Dousse, K. Fennane, M. Kavčič, Y. Kayser, J. Szlachetko, et al.(2009). Double K-shell photoionization of low-Z atoms and He-like ions . European Physical Journal: Special Topics. 169. (1). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 23--27. Springer Verlag

IVANOV, IA, KHEIFETS, AS(2009). Angular anisotropy parameters for sequential two-photon double ionization of helium . PHYSICAL REVIEW A. 79. (2).

IVANOV, IA, KHEIFETS, AS(2009). Calculation of HHG spectra in complex atoms . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 42. (14).

Kheifets, A. S., Naja, A., Casagrande, E. M. Staicu, Lahmam-Bennani, A. (2009). An energetic (e, 2e) reaction away from the Bethe ridge: recoil versus binary . Journal of Physics B: Atomic, Molecular and Optical Physics.

A. S. Kheifets(2009). Photoelectron angular correlation pattern in sequential two-photon double ionization of neon . Journal of Physics B: Atomic, Molecular and Optical Physics. 42. (13). Institute of Physics

I. A. Ivanov, A. S. Kheifets(2009). Calculation of HHG spectra in complex atoms . Journal of Physics B: Atomic, Molecular and Optical Physics. 42. (14). Institute of Physics

KHEIFETS, AS, NAJA, A, CASAGRANDE, EMS, LAHMAM-BENNANI, A(2009). An energetic (e, 2e) reaction away from the Bethe ridge: recoil versus binary . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 42. (16).

IVANOV, IA, KHEIFETS, AS(2009). Tailoring the waveforms to extend the high-order harmonic generation cutoff . PHYSICAL REVIEW A. 80. (2).

Hoszowska, J., Kheifets, A. K., Dousse, J. -Cl., Berset, M., Bray, I., Cao, W., Fennane, K., Kayser, Y., Kavcic, M., Szlachetko, J., et al. (2009). Physical Mechanisms and Scaling Laws of K-Shell Double Photoionization . Physical Review Letters.

Ivanov, I. A., Kheifets, A. S. (2009). Tailoring the waveforms to extend the high-order harmonic generation cutoff . Physical Review A.

A. S. Kheifets, A. Naja, E. M.Staicu Casagrande, A. Lahmam-Bennani(2009). An energetic (e, 2e) reaction away from the Bethe ridge . Journal of Physics B: Atomic, Molecular and Optical Physics. 42. (16). Institute of Physics

M. A. Stevenson, L. R. Hargreaves, B. Lohmann, I. Bray, D. V. Fursa, K. Bartschat, A. Kheifets (2009). Fully differential cross-section measurements for electron-impact ionization of neon and xenon . Physical Review A.

A. S. Kheifets, Igor Bray, J. Hoszowska (2009). <math display="inline"> <mi>K</mi> </math> -shell double photoionization of Be, Mg, and Ca . Physical Review A.

A. S. Kheifets, D. V. Fursa, I. Bray (2009). Two-electron photoionization of ground-state lithium . Physical Review A.

KHEIFETS, AS, FURSA, DV, BRAY, I(2009). Two-electron photoionization of ground-state lithium . PHYSICAL REVIEW A. 80. (6).

Ivanov, I. A., Kheifets, A. S. (2009). Harmonic generation for atoms in fields of varying ellipticity: Single-active-electron model with Hartree-Fock potential . Physical Review A.

STEVENSON, MA, HARGREAVES, LR, LOHMANN, B, BRAY, I, FURSA, DV, BARTSCHAT, K, KHEIFETS, A(2009). Fully differential cross-section measurements for electron-impact ionization of neon and xenon . PHYSICAL REVIEW A. 79. (1).

Ivanov, I. A., Kheifets, A. S. (2009). Above-threshold-ionization structures in photoelectron momentum distributions for single ionization of He by a strong electromagnetic field . Physical Review A.

Resonant enhancement of generation of harmonics @article{aafa631160fd4bf78ea39ae82830af83, title = "Resonant enhancement of generation of harmonics", abstract = "We develop a Floquet based formalism which describes a process of the generation harmonics of in an atom driven by a laser field. Using this formalism, we show that several harmonics are strongly enhanced in the spectrum when the laser frequency is such that a multiphoton resonance occurs between the initial state and a quasienergy state. We illustrate these findings by a numerical calculation of the harmonics generation in the potassium and rubidium atoms driven by a laser in the near-infrared energy range. The present formalism is also applicable when the initial state is a coherent superposition of several field-free atomic states.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2008", month = nov, day = "11", doi = "10.1103/PhysRevA.78.053406", language = "English", volume = "78", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Recoil-ion momentum distributions for two-photon double ionization of He and Ne by 44 eV free-electron laser radiation @article{3e35dab1818c4078bb24c6a45c8d4461, title = "Recoil-ion momentum distributions for two-photon double ionization of He and Ne by 44 eV free-electron laser radiation", abstract = "Recoil-ion momentum distributions for two-photon double ionization of He and Ne (ω=44eV) have been recorded with a reaction microscope at FLASH (the free-electron laser at Hamburg) at an intensity of ∼1×1014W/cm2 exploring the dynamics of the two fundamental two-photon-two-electron reaction pathways, namely, sequential and direct (or nonsequential) absorption of the photons. We find strong differences in the recoil-ion momentum patterns for the two mechanisms pointing to the significantly different two-electron emission dynamics and thus provide serious constraints for theoretical models.", author = "A. Rudenko and L. Foucar and M. Kurka and Th Ergler and K{\"u}hnel, \{K. U.\} and Jiang, \{Y. H.\} and A. Voitkiv and B. Najjari and A. Kheifets and S. L{\"u}demann and T. Havermeier and M. Smolarski and S. Sch{\"o}ssler and K. Cole and M. Sch{\"o}ffler and R. D{\"o}rner and S. D{\"u}sterer and W. Li and B. Keitel and R. Treusch and M. Gensch and Schr{\"o}ter, \{C. D.\} and R. Moshammer and J. Ullrich", year = "2008", month = aug, day = "15", doi = "10.1103/PhysRevLett.101.073003", language = "English", volume = "101", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "7", } . Physical Review Letters.

DWBA-G calculations of electron impact ionization of noble gas atoms @article{6bbb810da5104d4a849f841590f70190, title = "DWBA-G calculations of electron impact ionization of noble gas atoms", abstract = "We perform calculations of electron impact ionization of noble gas atoms within the distorted wave Born approximation (DWBA) corrected by the Gamow factor (G) to account for the post-collision interaction. We make an extensive comparison with experimental data on He 1s2, Ne 2s2, 2p6 and Ar 3p6 under kinematics characterized by large energy transfer and close to minimum momentum transfer from the projectile to the target. For all atoms, good agreement between theory and experiment is achieved. In the case of Ar, the disagreement of experimental data with theory reported earlier by Catoire et al (2006 J. Phys. B: At. Mol. Opt. Phys. 39 2827) is reconciled.", author = "Kheifets, \{A. S.\} and A. Naja and Casagrande, \{E. M.Staicu\} and A. Lahmam-Bennani", year = "2008", month = jul, day = "28", doi = "10.1088/0953-4075/41/14/145201", language = "English", volume = "41", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "14", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

High harmonics generation from excited states of atomic lithium @article{ca81c44945e448558bcd2b7e28ba9d06, title = "High harmonics generation from excited states of atomic lithium", abstract = "We present a calculation of the harmonics yield from the lithium atom exposed to an intense 3.5 νm mid-infrared laser pulse. Our calculation shows that a considerable increase of the yield of high harmonics generation (HHG) can be achieved if initially the atom is prepared in an excited 2p state. We show that this increase can be regarded as a resonant process due to appearance of a multiphoton resonance between the initial state and a quasienergy state. We also consider HHG from lithium prepared initially in a superposition of the ground and excited states.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2008", month = jun, day = "14", doi = "10.1088/0953-4075/41/11/115603", language = "English", volume = "41", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "11", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Perturbative calculation of two-photon double electron ionization of helium @article{ea7751c4734b4cd299795f54b99e63e9, title = "Perturbative calculation of two-photon double electron ionization of helium", abstract = "We report the total integrated cross-section (TICS) of two-photon double ionization of helium in the photon energy range from 40 to 54 eV. We compute the TICS in the lowest order perturbation theory (LOPT) using the length and Kramers-Henneberger gauges of the electromagnetic interaction. Our findings indicate that the LOPT gives results for the TICS in agreement with our earlier non-perturbative calculations.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2008", month = may, day = "14", doi = "10.1088/0953-4075/41/9/095002", language = "English", volume = "41", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "9", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

(e, 2e) triple differential cross-sections for ionization beyond helium @article{47583b18b4c54380902d053e27f35763, title = "(e, 2e) triple differential cross-sections for ionization beyond helium: The neon case at large energy transfer", abstract = "We report new coplanar (e, 2e) results for ionization of the He 1s and Ne 2p and 2s subshells under kinematics which have remained rather unexplored to date and characterized by large energy transfer and close to minimum momentum transfer from the projectile to the target. The experimental results obtained in two laboratories are used as a sensitive test of a number of state-of-the-art available theoretical models for multi-electron atoms. The He results are in excellent agreement with convergent close-coupling predictions as well as with distorted-wave + Gamow and hybrid distorted-wave + R-matrix models. In the Ne case, an overall satisfactory agreement with experiments is obtained for all considered models. The importance of post-collisional interaction effects is demonstrated whereas second-order effects in the projectile-target interaction at small distances are shown to be negligibly small. Remaining discrepancies between theories and experiments are discussed.", author = "A. Naja and Casagrande, \{E. M.Staicu\} and A. Lahmam-Bennani and M. Stevenson and B. Lohmann and \{Dal Cappello\}, C. and K. Bartschat and A. Kheifets and I. Bray and Fursa, \{D. V.\}", year = "2008", month = apr, day = "28", doi = "10.1088/0953-4075/41/8/085205", language = "English", volume = "41", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "8", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Photodouble ionization of He with circularly polarized synchrotron radiation @article{de6d9337053f405e840af26162c636f2, title = "Photodouble ionization of He with circularly polarized synchrotron radiation: Complete experiment and dynamic nodes", abstract = "The combination of measurements of the photodouble ionization (PDI) of He with linearly and circularly polarized synchrotron radiation has allowed to obtain experimentally the moduli and relative phase of the complex amplitudes needed for the complete description of the process. The same quantities have been used to calculate other observables of the process (linear dichroism, asymmetry parameter of the angular distribution of one of the two photoelectrons and He2+ recoil momentum distribution). Moreover, the present measurements prove definitely the existence of the dynamic nodes predicted by theories in the circular dichroism of PDI and associate them to a reduction of dimensionality of the process.", author = "P. Bolognesi and V. Feyer and A. Kheifets and S. Turchini and T. Prosperi and N. Zema and L. Avaldi", year = "2008", month = mar, day = "14", doi = "10.1088/0953-4075/41/5/051003", language = "English", volume = "41", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "5", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

The ionization of Mg by electron impact at 1000 eV studied by (e, 2e) experiments @article{11acfa946a684f1695c4a85003d6cc62, title = "The ionization of Mg by electron impact at 1000 eV studied by (e, 2e) experiments", abstract = "The ionization of Mg 3s and 2p and He 1s has been studied in (e, 2e) experiments at about 1000 eV incident energy and 20 eV ejected electron energy for a momentum transfer between 0.5 and 2.1 au. The comparison with the predictions of the distorted wave Born approximation model shows a generally good agreement between experiment and theory. The differences observed between the He and Mg angular distributions can be explained as an initial state effect and are attributed to the differences between the He 1s and Mg 3s wavefunctions in the momentum space.", author = "P. Bolognesi and H. Bohachov and V. Borovik and S. Veronesi and R. Flammini and E. Fainelli and A. Borovik and J. Martinez and Whelan, \{Colm T.\} and Walters, \{H. R.J.\} and A. Kheifets and L. Avaldi", year = "2008", month = jan, day = "14", doi = "10.1088/0953-4075/41/1/015201", language = "English", volume = "41", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "1", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

BOLOGNESI, P, BOHACHOV, H, BOROVIK, V, VERONESI, S, FLAMMINI, R, FAINELLI, E, BOROVIK, A, MARTINEZ, J, WHELAN, CT, WALTERS, HRJ, et al.(2008). The ionization of Mg by electron impact at 1000 eV studied by (e, 2e) experiments . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 41. (1).

IVANOV, IA, KHEIFETS, AS(2008). High harmonics generation from excited states of atomic lithium . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 41. (11).

NAJA, A, CASAGRANDE, EMS, LAHMAM-BENNANI, A, STEVENSON, M, LOHMANN, B, DAL CAPPELLO, C, BARTSCHAT, K, KHEIFETS, A, BRAY, I, FURSA, DV(2008). (e, 2e) triple differential cross-sections for ionization beyond helium: the neon case at large energy transfer . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 41. (8).

Bolognesi, P., Feyer, V., Kheifets, A., Turchini, S., Prosperi, T., Zema, N., Avaldi, L. (2008). Photodouble ionization of He with circularly polarized synchrotron radiation: complete experiment and dynamic nodes . Journal of Physics B: Atomic, Molecular and Optical Physics.

I A Ivanov, A S Kheifets (2008). Perturbative calculation of two-photon double electron ionization of helium . Journal of Physics B: Atomic, Molecular and Optical.

I A Ivanov, A S Kheifets (2008). High harmonics generation from excited states of atomic lithium . Journal of Physics B: Atomic, Molecular and Optical.

Naja, A., Casagrande, E. M. Staicu, Lahmam-Bennani, A., Stevenson, M., Lohmann, B., Dal Cappello, C., Bartschat, K., Kheifets, A., Bray, I., Fursa, D. V. (2008). (e, 2e) triple differential cross-sections for ionization beyond helium: the neon case at large energy transfer . Journal of Physics B: Atomic, Molecular and Optical Physics.

Rudenko, A., Foucar, L., Kurka, M., Ergler, Th., Kuehnel, K. U., Jiang, Y. H., Voitkiv, A., Najjari, B., Kheifets, A., Luedemann, S., et al. (2008). Recoil-ion momentum distributions for two-photon double ionization of He and Ne by 44 eV free-electron laser radiation . Physical Review Letters.

Kheifets, A. S., Naja, A., Casagrande, E. M. Staicu, Lahmam-Bennani, A. (2008). DWBA-G calculations of electron impact ionization of noble gas atoms . Journal of Physics B: Atomic, Molecular and Optical Physics.

Bolognesi, P., Bohachov, H., Borovik, V., Veronesi, S., Flammini, R., Fainelli, E., Borovik, A., Martinez, J., Whelan, Colm T., Walters, H. R. J., et al. (2008). The ionization of Mg by electron impact at 1000 eV studied by (e, 2e) experiments . Journal of Physics B: Atomic, Molecular and Optical Physics.

IVANOV, IA, KHEIFETS, AS(2008). Perturbative calculation of two-photon double electron ionization of helium . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 41. (9).

Ivanov, I. A., Kheifets, A. S. (2008). Resonant enhancement of generation of harmonics . Physical Review A.

E. M. Staicu Casagrande, A. Naja, A. Lahmam-Bennani, A. S. Kheifets, D. H. Madison, B. Joulakian(2008). New (e,2e) studies of atomic and molecular targets . Journal of Physics: Conference Series. 141. IOP Publishing Ltd.

BOLOGNESI, P, FEYER, V, KHEIFETS, A, TURCHINI, S, PROSPERI, T, ZEMA, N, AVALDI, L(2008). Photodouble ionization of He with circularly polarized synchrotron radiation: complete experiment and dynamic nodes . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 41. (5).

IVANOV, IA, KHEIFETS, AS(2008). Resonant enhancement of generation of harmonics . PHYSICAL REVIEW A. 78. (5).

KHEIFETS, AS, NAJA, A, CASAGRANDE, EMS, LAHMAM-BENNANI, A(2008). DWBA-G calculations of electron impact ionization of noble gas atoms . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 41. (14).

RUDENKO, A, FOUCAR, L, KURKA, M, ERGLER, T, KUHNEL, KU, JIANG, YH, VOITKIV, A, NAJJARI, B, KHEIFETS, A, LUDEMANN, S, et al.(2008). Recoil-ion momentum distributions for two-photon double ionization of He and Ne by 44 eV free-electron laser radiation . PHYSICAL REVIEW LETTERS. 101. (7).

Sequential two-photon double ionization of noble gas atoms @article{5020283033694bda822738718de05349, title = "Sequential two-photon double ionization of noble gas atoms", abstract = "We develop a formalism which describes sequential two-photon double ionization (TPDI) of a closed-shell atom. We apply this formalism to calculate the angular asymmetry parameters of sequential TPDI of the Ne 2p and Ar 3p valence subshells. Comparison with the latest experimental data is made.", author = "Kheifets, \{A. S.\}", year = "2007", month = nov, day = "28", doi = "10.1088/0953-4075/40/22/F02", language = "English", volume = "40", pages = "F313--F318", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "22", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Convergent close coupling calculations of two-photon double ionization of He @article{3c2fa4dfc91c4a3d8e8e9961a20b2a7a, title = "Convergent close coupling calculations of two-photon double ionization of He", abstract = "We review recent applications of the convergent close-coupling (CCC) method to studies of two-photon double ionization (TPDI) of He. In a weak-field regime, the electron-photon interaction can be treated within the lowest order perturbation theory (LOPT) whereas the electron-electron interaction is included in full. The intermediate states of the target can either be represented by a discrete set of B-splines in a box or summed over with an average weight (closure approximation). In a non-perturbative regime, we solve the time-dependent Schr{\"o}dinger equation on a square-integrable basis and project this solution on a set of CCC final states. In both regimes, we are able to calculate reliably the total intgrated and full differential TPDI cross-sections. Besides purely numerical results, we introduce a convenient analytical parametrization of the TPDI amplitude in the manner similar to single photon double ionization. Aided with this parametrization, we observe two distinctly different modes of correlated motion of the photoelectron pair. We also derive the angular anisotropy parameters and the recoil ion momentum distribution for TPDI of He. The latter can be compared with recent experimental observations.", author = "S. Kheifets and Ivanov, \{I. A.\} and I. Bray", year = "2007", month = nov, day = "1", doi = "10.1088/1742-6596/88/1/012051", language = "English", volume = "88", journal = "Journal of Physics: Conference Series", issn = "1742-6588", publisher = "IOP Publishing Ltd.", number = "1", } . Journal of Physics: Conference Series.

Angular anisotropy parameters and recoil-ion momentum distribution in two-photon double ionization of helium @article{62006a0a14814f8fa552071fda82cb14, title = "Angular anisotropy parameters and recoil-ion momentum distribution in two-photon double ionization of helium", abstract = "We present convergent-close-coupling (CCC) calculations of the angular anisotropy parameters β2, β4 and the recoil ion momentum distribution dσ dp in two-photon double ionization (TPDI) of helium. In a stark contrast to single-photon double ionization (SPDI), where the β2 parameter varies widely changing the angular distribution from isotropic to nearly dipole for slow and fast photoelectrons, respectively, the β parameters for TPDI show very little change. The angular distribution of the recoil ion is fairly isotropic in TPDI as opposed to a strong alignment with the polarization of light in SPDI.", author = "Kheifets, \{A. S.\} and Ivanov, \{I. A.\} and Igor Bray", year = "2007", month = aug, day = "28", doi = "10.1103/PhysRevA.76.025402", language = "English", volume = "76", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Single-photon double ionization of negative hydrogen ions in the presence of a dc electric field @article{7690c9a8a56647e599f06c599407064c, title = "Single-photon double ionization of negative hydrogen ions in the presence of a dc electric field", abstract = "We present an accurate numerical study of the influence an the external dc electric field on the process of single-photon double ionization of the negative hydrogen ion at photon energies from the threshold to 30 eV. We demonstrate that the presence of an external dc electric field of the order of 0.005 a.u. may considerably alter the cross section of the process.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2007", month = jun, day = "5", doi = "10.1103/PhysRevA.75.062701", language = "English", volume = "75", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

(e,3e) on helium at low impact energy @article{8a007ab64ce5437187d5882a9a447d04, title = "(e,3e) on helium at low impact energy: The strongly correlated three-electron continuum", abstract = "Double ionization of the helium atom by slow electron impact (E0=106eV) is studied in a kinematically complete experiment. Because of a low excess energy Eexc=27eV above the double ionization threshold, a strongly correlated three-electron continuum is realized. This is demonstrated by measuring and calculating the fully differential cross sections for equal energy sharing of the final-state electrons. While the electron emission is dominated by a strong Coulomb repulsion, also signatures of more complex dynamics of the full four-body system are identified.", author = "M. D{\"u}rr and A. Dorn and J. Ullrich and Cao, \{S. P.\} and A. Czasch and Kheifets, \{A. S.\} and G{\"o}tz, \{J. R.\} and Briggs, \{J. S.\}", year = "2007", month = may, day = "11", doi = "10.1103/PhysRevLett.98.193201", language = "English", volume = "98", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "19", } . Physical Review Letters.

Valence-shell double photoionization of alkaline-earth-metal atoms @article{a127198a004a4d67914e88d9f32b4188, title = "Valence-shell double photoionization of alkaline-earth-metal atoms", abstract = "We apply the convergent close-coupling formalism to describe direct double photoionization (DPI) of the valence n s2 shell of alkaline-earth-metal atoms: beryllium (n=2), magnesium (n=3), and calcium (n=4). We consider the range of photon energies below the onset of resonant and Auger ionization processes where the subvalent and core electrons can be treated as spectators. By comparing alkaline-earth-metal atoms with helium, we elucidate the role of the ground state and final ionized state correlations in DPI of various quasi-two-electron atoms.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2007", month = apr, day = "11", doi = "10.1103/PhysRevA.75.042703", language = "English", volume = "75", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "4", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Two-photon double ionization of helium in the region of photon energies 42-50 eV @article{2afd257d3f7049c9953fafd2e6f342e9, title = "Two-photon double ionization of helium in the region of photon energies 42-50 eV", abstract = "We report the total integrated cross section (TICS) of two-photon double ionization of helium in the photon energy range from 42 to 50 eV. Our computational procedure relies on a numerical solution of the time-dependent Schr{\"o}dinger equation on a square-integrable basis and subsequent projection of this solution on a set of final field-free states describing correlation in the two-electron continuum. Our results suggest that the TICS grows monotonically as a function of photon energy in the region of 42-50 eV, possibly reaching a maximum in the vicinity of 50 eV. We also present fully resolved triple-differential cross sections for selected photon energies.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2007", month = mar, day = "23", doi = "10.1103/PhysRevA.75.033411", language = "English", volume = "75", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "3", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Different escape modes in two-photon double ionization of helium @article{010ccee5d2154183831be98350134ba2, title = "Different escape modes in two-photon double ionization of helium", abstract = "The quadrupole channel of two-photon double ionization of He exhibits two distinctly different modes of correlated motion of the photoelectron pair. The kinematics of the mode associated with the center-of-mass motion favors large total momenta maximized at parallel emission where the interelectron repulsion is strong. In contrast, the mode associated with the relative motion favors large relative momenta maximized at antiparallel emission where the interelectron repulsion is relatively weak. This difference in the interelectron repulsion allows for much wider angular correlation width in the relative motion mode as compared to the center-of-mass mode.", author = "Kheifets, \{A. S.\} and Ivanov, \{A. I.\} and I. Bray", year = "2007", month = feb, day = "26", doi = "10.1103/PhysRevA.75.024702", language = "English", volume = "75", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

DURR, M, DORN, A, ULLRICH, J, CAO, SP, CZASCH, A, KHEIFETS, AS, GOTZ, JR, BRIGGS, JS(2007). (e,3e) on helium at low impact energy: The strongly correlated three-electron continuum . PHYSICAL REVIEW LETTERS. 98. (19).

Duerr, M., Dorn, A., Ullrich, J., Cao, S. P., Czasch, A., Kheifets, A. S., Goetz, J. R., Briggs, J. S. (2007). (e,3e) on helium at low impact energy: The strongly correlated three-electron continuum . Physical Review Letters.

Ivanov, I. A., Kheifets, A. S. (2007). Single-photon double ionization of negative hydrogen ions in the presence of a dc electric field . Physical Review A.

KHEIFETS, AS, IVANOV, IA, BRAY, I(2007). Angular anisotropy parameters and recoil-ion momentum distribution in two-photon double ionization of helium . PHYSICAL REVIEW A. 76. (2).

KHEIFETS, AS, IVANOV, AI, BRAY, I(2007). Different escape modes in two-photon double ionization of helium . PHYSICAL REVIEW A. 75.

IVANOV, IA, KHEIFETS, AS(2007). Two-photon double ionization of helium in the region of photon energies 42-50 eV . PHYSICAL REVIEW A. 75. (3).

Kheifets, A. S., Ivanov, I. A., Bray, Igor (2007). Angular anisotropy parameters and recoil-ion momentum distribution in two-photon double ionization of helium . Physical Review A.

Kheifets, A. S. (2007). Sequential two-photon double ionization of noble gas atoms . Journal of Physics B: Atomic, Molecular and Optical Physics.

Ivanov, I. A., Kheifets, A. S. (2007). Two-photon double ionization of helium in the region of photon energies 42-50 eV . Physical Review A.

A. S. Kheifets, Igor Bray (2007). Valence-shell double photoionization of alkaline-earth-metal atoms . Physical Review A.

KHEIFETS, AS, BRAY, I(2007). Valence-shell double photoionization of alkaline-earth-metal atoms . PHYSICAL REVIEW A. 75.

IVANOV, IA, KHEIFETS, AS(2007). Single-photon double ionization of negative hydrogen ions in the presence of a dc electric field . PHYSICAL REVIEW A. 75. (6).

Kheifets, A. S., Ivanov, A. I., Bray, I. (2007). Different escape modes in two-photon double ionization of helium . Physical Review A.

KHEIFETS, AS(2007). Sequential two-photon double ionization of noble gas atoms . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 40. (22). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString F313-F318.

Non-perturbative approach to multiphoton ionisation of the hydrogen and helium atoms @article{1e16f392bb1e4f67ba4e0bd22e4289da, title = "Non-perturbative approach to multiphoton ionisation of the hydrogen and helium atoms", abstract = "Laser light intensities, currently obtained in the laboratories, make it possible to observe many multi-photon phenomena in the interaction of light and matter (such as multi-photon ionisation or MPI process). Theoretical description of such phenomena necessitates the use of essentially non-perturbative framework. We present such an approach based on the recasting of the Schrodinger equation for the system atom+field into a set of coupled integral equations of the Lippmann-Schwinger type.", keywords = "Kramers-Henneberger Hamiltonian, Multi-photon ionisation, Non-perturbative phenomena, Strong laser fields", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2006", month = nov, doi = "10.1016/j.radphyschem.2005.07.066", language = "English", volume = "75", pages = "2102--2104", journal = "Radiation Physics and Chemistry", issn = "0969-806X", publisher = "Elsevier Ltd.", number = "11 SPEC. ISS.", } . Radiation Physics and Chemistry.

Satellite structure in Auger and (e, 2 e) spectra of germanium @article{75de6e99e0e945409cccfd9c25d2034b, title = "Satellite structure in Auger and (e, 2 e) spectra of germanium", abstract = "The interpretation of electron spectroscopy data is often complicated by the presence of satellites. These satellites are either due to different final states reached after the excitation (intrinsic satellites) or due to energy loss experienced by the escaping electron on its way out the target (extrinsic satellites). Unravelling these two contributions in an unambiguous way is difficult. In this paper we compare the intrinsic satellite structures obtained for germanium by two different high-energy spectroscopies: Auger spectroscopy of deep core levels and valence band electron momentum spectroscopy. Despite the different nature of the two probes we find a similar shape of the intrinsic satellites and comparable intensity.", keywords = "Auger electron spectroscopy, Electron momentum spectroscopy, Germanium", author = "Went, \{M. R.\} and M. Vos and Kheifets, \{A. S.\}", year = "2006", month = nov, doi = "10.1016/j.radphyschem.2006.09.003", language = "English", volume = "75", pages = "1698--1703", journal = "Radiation Physics and Chemistry", issn = "0969-806X", publisher = "Elsevier Ltd.", number = "11 SPEC. ISS.", } . Radiation Physics and Chemistry.

Elastic and inelastic scattering in electron momentum spectroscopy of amorphous Ge films @article{aaae02d68a2246ac808604e365e1341e, title = "Elastic and inelastic scattering in electron momentum spectroscopy of amorphous Ge films", abstract = "Electron momentum spectroscopy (an (e, 2e) experiment in the high-energy and large momentum transfer limit) is a scattering approach to the study of the electronic structure. The intensity observed in these experiment is, for an infinitely thin film, simply proportional to the spectral momentum density. For experiments using free-standing films of a more realistic thickness (100 {\AA} or so), elastic and inelastic multiple scattering events are frequent and their influence on the observed intensity cannot be neglected. Here we study germanium films where the sp derived valence band can be measured simultaneously with the shallow, non-dispersing, 3d level. Somewhat surprisingly, the intensity of the 3d level, relative to that of the valence band, increases with film thickness. This effect is attributed to elastic multiple scattering. Monte Carlo simulations reproduce the changes in the observed intensity distributions with increasing film thickness.", keywords = "Electron momentum spectroscopy, Germanium, Multiple scattering", author = "Went, \{M. R.\} and M. Vos and Kheifets, \{A. S.\}", year = "2006", month = jun, doi = "10.1016/j.elspec.2006.03.005", language = "English", volume = "152", pages = "78--86", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", number = "1-2", } . Journal of Electron Spectroscopy and Related Phenomena.

Helium atom in presence of DC and AC electric fields @article{ca32783a8c0a4b26b90d15f0ec870f3b, title = "Helium atom in presence of DC and AC electric fields", abstract = "We investigate the effect of a static electric field on photoionization of the He atom in the ground IS and low-lying 2S and 2P excited states. The field-affected ionization potential and photoionization crosssection are determined from the complex eigenvalues of the time-dependent Schr{\"o}dinger equation solved by the complex rotation method in the Floquet ansatz. Accuracy of the method is enhanced by the use of the Hylleraas basis set. For the ground state of helium, we find that the total photoionization cross-section remains constant or decreases as a function of the DC field strength until this field reaches a certain critical value. For the low-lying excited states, effect of the static field is similar to the ordinary DC Stark effect.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2006", month = jun, doi = "10.1140/epjd/e2006-00061-y", language = "English", volume = "38", pages = "471--479", journal = "European Physical Journal D", issn = "1434-6060", publisher = "Springer Science+Business Media B.V.", number = "3", } . European Physical Journal D.

Helium atom in the monochromatic electromagnetic field @article{d70f2c926fcb45688c3c7d1fee126378, title = "Helium atom in the monochromatic electromagnetic field: AAAA Hylleraas basis treatment", abstract = "We apply a non-perturbative procedure for the calculation of the total photoionization cross-section of two-electron atomic systems. The procedure is based on the Floquet-Fourier representation of the time-dependent Schr{\"o}dinger equation. With the use of the Hylleraas-type basis functions, the total photoionization cross-sections obtained are within the accuracy of a fraction of a percent, which, we believe, is the most accurate estimate for the cross-sections available. The total photoionization cross-sections for neutral helium deviate notably from the benchmark experimental data [J.A.R. Samson et al., J. Phys. B 27, 887 (1994)].", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2006", month = may, doi = "10.1140/epjd/e2005-00334-y", language = "English", volume = "38", pages = "249--255", journal = "European Physical Journal D", issn = "1434-6060", publisher = "Springer Science+Business Media B.V.", number = "2", } . European Physical Journal D.

Photodouble ionization studies of the Ne(2s2) state under unequal energy sharing conditions @article{6eb1dedccb0444b19d9c2ac7f6d062f7, title = "Photodouble ionization studies of the Ne(2s2) state under unequal energy sharing conditions", abstract = "The triple differential cross section (TDCS) of the He2+(1s -2) and Ne2+(2s-2) states has been studied under unequal energy sharing conditions and perpendicular geometry, for a ratio of about 3 between the energies of the two ejected electrons. The dynamical quantities which govern the photodouble ionization (PDI) process, i.e. the squared moduli of the gerade and ungerade complex amplitudes and the cosine of their relative phase, have been extracted from the experimental data. The results from the two targets have been compared between themselves as well as with the theoretical predictions of the SC3 and convergent close coupling (CCC) calculations. This work represents a joint experimental and theoretical approach to the investigation of PDI of atomic systems with more than two electrons.", author = "P. Bolognesi and A. Kheifets and S. Otranto and M. Coreno and V. Feyer and Colavecchia, \{F. D.\} and Garibotti, \{C. R.\} and L. Avaldi", year = "2006", month = apr, day = "28", doi = "10.1088/0953-4075/39/8/008", language = "English", volume = "39", pages = "1899--1912", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "8", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Convergent close-coupling calculations of two-photon double ionization of helium @article{f6f105d97da64c688d1aca3033e81046, title = "Convergent close-coupling calculations of two-photon double ionization of helium", abstract = "We apply the convergent close-coupling (CCC) formalism to the problem of two-photon double ionization of helium. The electron-photon interaction is treated perturbatively whereas the electron-electron interaction is included in full. The integrated two-photon double ionization cross-section is substantially below non-perturbative literature results. However, the pattern of the angular correlation in the two-electron continuum is remarkably close to the non-perturbative time-dependent close-coupling calculation of Hu et al (2005 J. Phys. B: At. Mol. Opt. Phys. 38 L35).", author = "Kheifets, \{A. S.\} and Ivanov, \{I. A.\}", year = "2006", month = apr, day = "14", doi = "10.1088/0953-4075/39/7/015", language = "English", volume = "39", pages = "1731--1742", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "7", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Nondipole effects in double photoionization of He at 450 eV excess energy @article{23df283de89c4f59b182a68e1b89af6a, title = "Nondipole effects in double photoionization of He at 450 eV excess energy", abstract = "Convergent close-coupling results for the triply differential cross section for double photoionization of He that include dipole-quadrupole terms are shown to have improved agreement (as compared to dipole approximation results) with recent experiments using linearly polarized light (Knapp A et al 2005 J. Phys. B: At. Mol. Opt. Phys. 38 615) for a number of kinematical configurations.", author = "Istomin, \{Andrei Y.\} and Starace, \{Anthony F.\} and Manakov, \{N. L.\} and Meremianin, \{A. V.\} and Kheifets, \{A. S.\} and Igor Bray", year = "2006", month = jan, day = "28", doi = "10.1088/0953-4075/39/2/L03", language = "English", volume = "39", pages = "L35--L43", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "2", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

M. Vos, C. Bowles, A. S. Kheifets, M. R. Went(2006). Band structure of silicon as measured in extended momentum space . Physical Review B - Condensed Matter and Materials Physics. 73. (8). American Physical Society

IVANOVA, IA, KHEIFETS, AS(2006). Helium atom in presence of DC and AC electric fields . EUROPEAN PHYSICAL JOURNAL D. 38. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 471-479.

A. S. Kheifets, I. Bray(2006). Angular correlation in the two-electron continuum . Physical Review A - Atomic, Molecular, and Optical Physics. 73. (2). American Physical Society

Andrei Y Istomin, Anthony F Starace, N L Manakov, A V Meremianin, A S Kheifets, Igor Bray (2006). Nondipole effects in double photoionization of He at 450 eV excess energy . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS, BRAY, I(2006). Angular correlation in the two-electron continuum . PHYSICAL REVIEW A. 73. (2).

ISTOMIN, AY, STARACE, AF, MANAKOV, NL, MEREMIANIN, AV, KHEIFETS, AS, BRAY, I(2006). Nondipole effects in double photoionization of He at 450 eV excess energy . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 39. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L35-L43.

A. S. Kheifets, I. Bray (2006). Angular correlation in the two-electron continuum . Physical Review A.

M. Vos, C. Bowles, A. S. Kheifets, M. R. Went (2006). Band structure of silicon as measured in extended momentum space . Physical Review B.

IVANOV, IA, KHEIFETS, AS(2006). Single-photon double ionization of helium in the presence of dc electric field . PHYSICAL REVIEW A. 74. (4).

Ivanova, IA, Kheifets, AS (2006). Helium atom in presence of DC and AC electric fields . The European Physical Journal D.

I. A. Ivanov, A. S. Kheifets(2006). Single-photon double ionization of helium in the presence of dc electric field . Physical Review A - Atomic, Molecular, and Optical Physics. 74. (4). American Physical Society

KHEIFETS, AS, IVANOV, IA(2006). Convergent close-coupling calculations of two-photon double ionization of helium . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 39. (7). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1731-1742.

AS Kheifets, Went, M.R. Went, M Vos, A.S. Kheifets (2006). Elastic and inelastic scattering in electron momentum spectroscopy of amorphous Ge films . Journal of Electron Spectroscopy and Related Phenomena.

Ivanov, IA, Kheifets, AS (2006). Helium atom in the monochromatic electromagnetic field . The European Physical Journal D.

WENT, MR, VOS, M, KHEIFETS, AS(2006). Elastic and inelastic scattering in electron momentum spectroscopy of amorphous Ge films . JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. 152. (1-2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 78-86.

VOS, M, BOWLES, C, KHEIFETS, AS, WENT, MR(2006). Band structure of silicon as measured in extended momentum space . PHYSICAL REVIEW B. 73. (8).

IVANOV, IA, KHEIFETS, AS(2006). Helium atom in the monochromatic electromagnetic field . EUROPEAN PHYSICAL JOURNAL D. 38. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 249-255.

BOLOGNESI, P, KHEIFETS, A, OTRANTO, S, CORENO, M, FEYER, V, COLAVECCHIA, FD, GARIBOTTI, CR, AVALDI, L(2006). Photodouble ionization studies of the Ne(2s(2)) state under unequal energy sharing conditions . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 39. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1899-1912.

A S Kheifets, I A Ivanov (2006). Convergent close-coupling calculations of two-photon double ionization of helium . Journal of Physics B: Atomic, Molecular and Optical.

Ivanov, I. A., Kheifets, A. S. (2006). Single-photon double ionization of helium in the presence of dc electric field . Physical Review A.

Bolognesi, P., Kheifets, A., Otranto, S., Coreno, M., Feyer, V., Colavecchia, F. D., Garibotti, C. R., Avaldi, L. (2006). Photodouble ionization studies of the Ne(2s<SUP>2</SUP>) state under unequal energy sharing conditions . Journal of Physics B: Atomic, Molecular and Optical Physics.

Partial photoionization cross sections and angular distributions for double excitation of helium up to the N=13 threshold @article{e7c094b162e6468ca3e7e94717ae2081, title = "Partial photoionization cross sections and angular distributions for double excitation of helium up to the N=13 threshold", abstract = "Partial photoionization cross sections σN(Eγ) and photoelectron angular distributions βN(Eγ) were measured for the final ionic states He+(N>4) in the region between the N=8 and N=13 thresholds (Eγ>78.155eV) using the cold target recoil ion momentum spectroscopy technique (COLTRIMS). Comparison of the experimental data with two independent sets of theoretical predictions reveals disagreement for the branching ratios to the various HeN+ states. The angular distributions just below the double ionization threshold suggest an excitation process for highly excited N states similar to the Wannier mechanism for double ionization.", author = "A. Czasch and M. Sch{\"o}ffler and M. Hattass and S. Sch{\"o}ssler and T. Jahnke and Th Weber and A. Staudte and J. Titze and C. Wimmer and S. Kammer and M. Weckenbrock and S. Voss and Grisenti, \{R. E.\} and O. Jagutzki and Schmidt, \{L. Ph H.\} and H. Schmidt-B{\"o}cking and R. D{\"o}rner and Rost, \{J. M.\} and T. Schneider and Liu, \{Chien Nan\} and I. Bray and Kheifets, \{A. S.\} and K. Bartschat", year = "2005", month = dec, day = "9", doi = "10.1103/PhysRevLett.95.243003", language = "English", volume = "95", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "24", } . Physical Review Letters.

Spectral momentum densities of vanadium and vanadium oxide as measured by high energy (e, 2e) spectroscopy @article{d317d4b184c34b5bb1c4ce35908323b6, title = "Spectral momentum densities of vanadium and vanadium oxide as measured by high energy (e, 2e) spectroscopy", abstract = "The spectral momentum densities of vanadium metal and V2O 3 are measured by electron momentum spectroscopy. Results are compared with band structure calculations based on density functional theory (DFT). Qualitatively, the agreement between theory and experiment is good. The calculated total band width of vanadium metal (6.5 eV) is in excellent agreement with the observed one (6.5 ± 0.25 eV). The splitting between the outer and inner valence bands in V2O3 is 2 eV larger in the experiment than in the density functional theory calculation. The observed momentum distributions agree reasonably well with the calculated distributions with the exception of the intensity of the outer valence band relative to the inner valence band in V2O3: the outer valence band is less intense than calculated. The momentum density near the Fermi level in V metal resembles that of atomic V 3d orbitals. However, momentum profiles of the V 3d orbitals in V2O3 are much more sharply peaked than the atomic 3d orbital in both the theory and experiment. Correlation effects are discussed and theoretical problems in describing EMS data from narrow band systems are identified.", author = "C. Chen and Gale, \{M. N.\} and Kheifets, \{A. S.\} and M. Vos and Went, \{M. R.\}", year = "2005", month = dec, day = "7", doi = "10.1088/0953-8984/17/48/019", language = "English", volume = "17", pages = "7689--7704", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "48", } . Journal of Physics Condensed Matter.

Parametrizations and dynamical analysis of angle-integrated cross sections for double photoionization including nondipole effects @article{6489e85297334939ac499817580fabf0, title = "Parametrizations and dynamical analysis of angle-integrated cross sections for double photoionization including nondipole effects", abstract = "Similarly to differential cross sections for one-electron photoionization, the doubly differential cross section for double photoionization (DPI) may be conveniently described by four parameters: the singly differential (with respect to energy sharing) cross section (σ0), the dipole asymmetry parameter (β), and two nondipole asymmetry parameters (Y and δ). Here we derive two model-independent representations for these parameters for DPI from a S01 atomic bound state: (i) in terms of one-dimensional integrals of the polarization-invariant DPI amplitudes and (ii) in terms of the exact two-electron reduced matrix elements. For DPI of He at excess energies, Eexc, of 100 eV, 450 eV, and 1 keV, we present numerical results for the asymmetry parameters within the framework of the convergent close-coupling theory and compare them with results of lowest-order (in the interelectron interaction) perturbation theory (LOPT). The results for Eexc=1keV exhibit a nondipole asymmetry that is large enough to be easily measured experimentally. We find excellent agreement between our LOPT results and other theoretical predictions and experimental data for total cross sections and ratios of double to single ionization cross sections for K-shell DPI from several multielectron atoms.", author = "Istomin, \{Andrei Y.\} and Starace, \{Anthony F.\} and Manakov, \{N. L.\} and Meremianin, \{A. V.\} and Kheifets, \{A. S.\} and Igor Bray", year = "2005", month = nov, doi = "10.1103/PhysRevA.72.052708", language = "English", volume = "72", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Electron momentum spectroscopy of light and heavy targets @article{1156face28e749cba90e1c6837d6689d, title = "Electron momentum spectroscopy of light and heavy targets", abstract = "Electron momentum spectroscopy (EMS) measures the spectral function of electrons in matter directly, provided that multiple scattering effects are negligibly small. Even for the thinnest films this is not the case and one has to correct for multiple scattering effects in order to retrieve the spectral function. Both elastic and inelastic scattering effects affect the measurement. Elastic scattering is expected to increase greatly with increasing atomic number, much more so than inelastic scattering. For this reason EMS was thought to be of limited value for heavy targets. Here, we present data for carbon, silicon and gold and show that they are affected in different ways by multiple scattering. The gold sample has poor count rate, but in the spectra the multiple scattering effects appear rather minor. Carbon and silicon on the other hand have good count rates, but the spectra are strongly affected by multiple scattering. Monte Carlo simulations are used to try to understand these effects. Rather surprisingly the EMS spectra for heavy elements are of comparable quality to those of lighter elements.", keywords = "Elastic scattering, Electron momentum spectroscopy, Inelastic scattering band structure", author = "M. Vos and C. Bowles and Kheifets, \{A. S.\} and Went, \{M. R.\}", year = "2005", month = nov, doi = "10.1016/j.elspec.2005.06.002", language = "English", volume = "149", pages = "20--28", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", number = "1-3", } . Journal of Electron Spectroscopy and Related Phenomena.

Double photoionization of He and H2 at unequal energy sharing @article{ab2ebfe4fbc040878dbd8729c18e083b, title = "Double photoionization of He and H2 at unequal energy sharing", abstract = "A recently developed single-center model of double photoionization (DPI) of the H2 molecule [Kheifets, Phys. Rev. A 71, 022704 (2005)] has been extended to represent the DPI process at unequal energy sharing. The model is applied to describe the shape of the fully-differential cross-section (FDCS) of a randomly oriented hydrogen molecule in the isotopic form of D2 at the kinematics of recent experiments. Comparison with analogous FDCS for the He atom helps to elucidate the molecular effects.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2005", month = aug, doi = "10.1103/PhysRevA.72.022703", language = "English", volume = "72", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Triple coincidence (e,γ2e) experiment for simultaneous electron impact ionization excitation of helium @article{1fb21b47a40e48f182889adeb520ced7, title = "Triple coincidence (e,γ2e) experiment for simultaneous electron impact ionization excitation of helium", abstract = "Simultaneous ionization and excitation of helium atoms by 500 eV electron impact is observed by a triple coincidence of an ionized slow electron, the recoiling He+ ion, and the radiated vacuum ultraviolet photon (λ≤30.4nm). Kinematically complete differential cross sections are presented for the He+(2p)2P final ionic state, demonstrating the feasibility of a quantum mechanically complete experiment. The experimental data are compared to predictions from state-of-the-art numerical calculations. For large momentum transfers, a first-order treatment of the projectile-target interaction can reproduce the experimental angular dependence, but a second-order treatment is required to obtain consistent magnitudes.", author = "G. Sakhelashvili and A. Dorn and C. H{\"o}hr and J. Ullrich and Kheifets, \{A. S.\} and J. Lower and K. Bartschat", year = "2005", month = jul, day = "15", doi = "10.1103/PhysRevLett.95.033201", language = "English", volume = "95", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "3", } . Physical Review Letters.

On the use of the Kramers-Henneberger Hamiltonian in multi-photon ionization calculations @article{42a81b76cdc44162a4a3f5af76d0fb6f, title = "On the use of the Kramers-Henneberger Hamiltonian in multi-photon ionization calculations", abstract = "We employ the Kramers-Henneberger Hamiltonian for time-independent calculations of two-photon ionization of atoms with one and two electrons. As compared to the electromagnetic interaction in the length and velocity gauges, the presently employed Kramers-Henneberger gauge has an advantage of the dipole matrix elements for the free-free electron transitions being finite and well-defined quantities. This circumstance simplifies considerably the computations and allows us to obtain accurate results for the two-photon ionization of realistic atomic systems.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2005", month = jul, day = "14", doi = "10.1088/0953-4075/38/13/016", language = "English", volume = "38", pages = "2245--2255", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "13", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Lippmann-Schwinger description of multiphoton ionization @article{99e2853800d14d41a6fe0e2cf0f9fc6a, title = "Lippmann-Schwinger description of multiphoton ionization", abstract = "We outline a formalism and develop a computational procedure to treat the process of multiphoton ionization (MPI) of atomic targets in strong laser fields. We treat the MPI process nonperturbatively as a decay phenomenon by solving a coupled set of the integral Lippmann-Schwinger equations. As basic building blocks of the theory, we use a complete set of field-free atomic states, discrete and continuous. This approach should enable us to provide both the total and differential cross sections of MPI of atoms with one and two electrons. As an illustration, we apply the proposed procedure to a simple model of MPI from a square-well potential and to the hydrogen atom.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", year = "2005", month = apr, doi = "10.1103/PhysRevA.71.043405", language = "English", volume = "71", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "4", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Photo double ionization of helium 100 eV and 450 eV above threshold @article{e33665f0ae55429a919a1d95dbc37f1e, title = "Photo double ionization of helium 100 eV and 450 eV above threshold: II. Circularly polarized light", abstract = "We present a joint experimental and theoretical study of the fully differential cross section of the photo double ionization of helium with left and right circularly polarized light at Eexc= 100 eV and 450 eV above the threshold. We analyse angular distributions for the slow electron and the normalized circular dichroism for various energy sharings of the excess energy between the two electrons. The experimental results are well reproduced by convergent close coupling calculations.", author = "A. Knapp and A. Kheifets and I. Bray and Th Weber and Landers, \{A. L.\} and S. Sch{\"o}ssler and T. Jahnke and J. Nickles and S. Kammer and O. Jagutzki and Schmidt, \{L. Ph L.\} and M. Sch{\"o}ffler and T. Osipov and Prior, \{M. H.\} and H. Schmidt-B{\"o}cking and Cocke, \{C. L.\} and R. D{\"o}rner", year = "2005", month = mar, day = "28", doi = "10.1088/0953-4075/38/6/002", language = "English", volume = "38", pages = "635--643", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "6", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Photo double ionization of helium 100 eV and 450 eV above threshold @article{12b5b9d46d614830911d5e595e03234c, title = "Photo double ionization of helium 100 eV and 450 eV above threshold: I. Linearly polarized light", abstract = "We present a joint experimental and theoretical study for the fully differential cross section of the photo double ionization (PDI) of helium with linearly polarized light at the excess energies Eexc = 100 eV and 450 eV above the threshold. The fully differential cross section is obtained by measuring the three-dimensional momentum vectors of one electron and the He 2+ ion in coincidence using the COLTRIMS method. We give an overview of the momentum distribution of the three-body continuum 100 eV above the threshold. We show angular distributions for both electrons for various energy sharings at Eexc = 100 eV and 450 eV. The experimental results are well reproduced by a set of convergent close-coupling (CCC) calculations.", author = "A. Knapp and A. Kheifets and I. Bray and Th Weber and Landers, \{A. L.\} and S. Sch{\"o}ssler and T. Jahnke and J. Nickles and S. Kammer and O. Jagutzki and Schmidt, \{L. Ph L.\} and M. Sch{\"o}ffler and T. Osipov and Prior, \{M. H.\} and H. Schmidt-B{\"o}cking and Cocke, \{C. L.\} and R. D{\"o}rner", year = "2005", month = mar, day = "28", doi = "10.1088/0953-4075/38/6/001", language = "English", volume = "38", pages = "615--633", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "6", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Photo double ionization of helium 100 eV and 450 eV above threshold @article{bcf77087573f4e298dd7dbc4b203509a, title = "Photo double ionization of helium 100 eV and 450 eV above threshold: III. Gerade and ungerade amplitudes and their relative phases", abstract = "We present a joint experimental and theoretical study of the gerade and ungerade amplitudes of the photo double ionization of helium at excess energies of 100 eV and 450 eV above the threshold. We describe a method of extracting the amplitudes from a COLTRIMS data set. The experimental results are well reproduced by convergent close-coupling (CCC) calculations. The fully differential cross section data underlying this study can be found in our companion papers immediately preceding this one.", author = "A. Knapp and B. Kr{\"a}ssig and A. Kheifets and I. Bray and Th Weber and Landers, \{A. L.\} and S. Sch{\"o}ssler and T. Jahnke and J. Nickles and S. Kammer and O. Jagutzki and Schmidt, \{L. Ph L.\} and M. Sch{\"o}ffler and T. Osipov and Prior, \{M. H.\} and H. Schmidt-B{\"o}cking and Cocke, \{C. L.\} and R. D{\"o}rner", year = "2005", month = mar, day = "28", doi = "10.1088/0953-4075/38/6/003", language = "English", volume = "38", pages = "645--657", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "6", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Reply to "comment on 'Appearance and disappearance of the second Born effects in the (e,3e) reaction on He'" @article{4d17e497061340e9bcc862796fdd6fd3, title = "Reply to {"}comment on 'Appearance and disappearance of the second Born effects in the (e,3e) reaction on He'{"}", abstract = "In this Reply, we demonstrate that at large momentum transfer (q =2 a.u.), within the experimentally accessible angular range of the ionized electrons, there is good agreement between experiment and the first Born calculation concerning the shape of the cross section. Furthermore, we show that the fact that our results for (e,3e) double ionization seemingly {"}contradict well-accepted results in (e,2e) single ionization{"} can be traced to a second Born process in which the projectile interacts with both target electrons in sequence. This process competes effectively with other double ionization mechanisms but is relatively unimportant for single ionization.", author = "A. Dorn and A. Kheifets and Schr{\"o}ter, \{C. D.\} and C. H{\"o}hr and G. Sakhelashvili and R. Moshammer and J. Lower and J. Ullrich", year = "2005", month = feb, day = "1", doi = "10.1103/PhysRevA.71.026702", language = "English", volume = "71", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Single-center model for double photoionization of the H2 molecule @article{fef7e28a03d540dab1db633723665dbe, title = "Single-center model for double photoionization of the H2 molecule", abstract = "We present a single-center model of double photoionization (DPI) of the H2 molecule which combines a multiconfiguration expansion of the molecular ground state with the convergent close-coupling description of the two-electron continuum. Because the single-center final-state wave function is only correct in the asymptotic region of large distances, the model cannot predict the magnitude of the DPI cross sections. However, we expect the model to account for the angular correlation in the two-electron continuum and to reproduce correctly the shape of the fully differential DPI cross sections. We test this assumption in kinematics of recent DPI experiments on the randomly oriented and fixed in space hydrogen molecule in the isotopic form of D2.", author = "Kheifets, \{A. S.\}", year = "2005", month = feb, day = "1", doi = "10.1103/PhysRevA.71.022704", language = "English", volume = "71", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

ISTOMIN, AY, STARACE, AF, MANAKOV, NL, MEREMIANIN, AV, KHEIFETS, AS, BRAY, I(2005). Parametrizations and dynamical analysis of angle-integrated cross sections for double photoionization including nondipole effects . PHYSICAL REVIEW A. 72. (5).

C Chen, M N Gale, A S Kheifets, M Vos, M R Went (2005). Spectral momentum densities of vanadium and vanadium oxide as measured by high energy (e, 2e) spectroscopy . Journal of Physics: Condensed Matter.

KHEIFETS, AS, BRAY, I(2005). Double photoionization of He and H-2 at unequal energy sharing . PHYSICAL REVIEW A. 72.

KNAPP, A, KHEIFETS, A, BRAY, I, WEBER, T, LANDERS, AL, SCHOSSLER, S, JAHNKE, T, NICKLES, J, KAMMER, S, JAGUTZKI, O, et al.(2005). Photo double ionization of helium 100 eV and 450 eV above threshold: II. Circularly polarized light . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 38. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 635-643.

Czasch, A, Sch&#246;ffler, M, Hattass, M, Sch&#246;ssler, S, Jahnke, T, Weber, T, Staudte, A, Titze, J, Wimmer, C, Kammer, S, et al. (2005). Partial photoionization cross sections and angular distributions for double excitation of helium up to the <i>N</i>=13 threshold -: art. no. 243003 . Physical Review Letters.

IVANOV, IA, KHEIFETS, AS(2005). Lippmann-Schwinger description of multiphoton ionization . PHYSICAL REVIEW A. 71. (4).

A. S. Kheifets, Igor Bray (2005). Double photoionization of He and <math display="inline"> <msub> <mi mathvariant="normal">H</mi> <mn>2</mn> </msub> </math> at unequal energy sharing . Physical Review A.

Czasch, A, Schoffler, M, Hattass, M, Schossler, S, Jahnke, T, Weber, T, Staudte, A, Titze, J, Wimmer, C, Kammer, S, et al.(2005). Partial photoionization cross sections and angular distributions for double excitation of helium up to the N=13 threshold . Physical Review Letters. 95.

IVANOV, IA, KHEIFETS, AS(2005). On the use of the Kramers-Henneberger Hamiltonian in multi-photon ionization calculations . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 38. (13). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2245-2255.

Ivanov, IA, Kheifets, AS (2005). Lippmann-Schwinger description of multiphoton ionization . Physical Review A.

CHEN, C, GALE, MN, KHEIFETS, AS, VOS, M, WENT, MR(2005). Spectral momentum densities of vanadium and vanadium oxide as measured by high energy (e, 2e) spectroscopy . JOURNAL OF PHYSICS-CONDENSED MATTER. 17. (48). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 7689-7704.

M. Vos, C. Bowles, A.S. Kheifets, M.R. Went (2005). Electron momentum spectroscopy of light and heavy targets . Journal of Electron Spectroscopy and Related Phenomena.

Sakhelashvili, G, Dorn, A, Hohr, C, Ullrich, J, Kheifets, AS, Lower, J, Bartschat, K (2005). Triple coincidence (e,gamma 2e) experiment for simultaneous electron impact ionization excitation of helium . Physical Review Letters.

Knapp, A, Kheifets, A, Bray, I, Weber, T, Landers, AL, Sch&#246;ssler, S, Jahnke, T, Nickles, J, Kammer, S, Jagutzki, O, et al. (2005). Photo double ionization of helium 100 eV and 450 eV above threshold: I. Linearly polarized light . Journal of Physics B: Atomic, Molecular and Optical Physics.

I A Ivanov, A S Kheifets (2005). On the use of the Kramers-Henneberger Hamiltonian in multi-photon ionization calculations . Journal of Physics B: Atomic, Molecular and Optical Physics.

Sakhelashvili, G, Dorn, A, Hohr, C, Ullrich, J, Kheifets, AS, Lower, J, Bartschat, K(2005). Triple coincidence (e,gamma 2e) experiment for simultaneous electron impact ionization excitation of helium . Physical Review Letters. 95. (3).

KNAPP, A, KRASSIG, B, KHEIFETS, A, BRAY, I, WEBER, T, LANDERS, AL, SCHOSSLER, S, JAHNKE, T, NICKLES, J, KAMMER, S, et al.(2005). Photo double ionization of helium 100 eV and 450 eV above threshold: III. Gerade and ungerade amplitudes and their relative phases . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 38. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 645-657.

Knapp, A, Kr&#228;ssig, B, Kheifets, A, Bray, I, Weber, T, Landers, AL, Sch&#246;ssler, S, Jahnke, T, Nickles, J, Kammer, S, et al. (2005). Photo double ionization of helium 100 eV and 450 eV above threshold: III. Gerade and ungerade amplitudes and their relative phases . Journal of Physics B: Atomic, Molecular and Optical Physics.

A. S. Kheifets (2005). Single-center model for double photoionization of the H-2 molecule . Physical Review A.

KHEIFETS, AS(2005). Single-center model for double photoionization of the H-2 molecule . PHYSICAL REVIEW A. 71. (2).

VOS, M, BOWLES, C, KHEIFETS, AS, WENT, MR(2005). Electron momentum spectroscopy of light and heavy targets . JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. 149. (1-3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 20-28.

Knapp, A, Kheifets, A, Bray, I, Weber, T, Landers, AL, Sch&#246;ssler, S, Jahnke, T, Nickles, J, Kammer, S, Jagutzki, O, et al. (2005). Photo double ionization of helium 100 eV and 450 eV above threshold: II. Circularly polarized light . Journal of Physics B: Atomic, Molecular and Optical Physics.

Istomin, AY, Starace, AF, Manakov, NL, Meremianin, AV, Kheifets, AS, Bray, I (2005). Parametrizations and dynamical analysis of angle-integrated cross sections for double photoionization including nondipole effects . Physical Review A.

KNAPP, A, KHEIFETS, A, BRAY, I, WEBER, T, LANDERS, AL, SCHOSSLER, S, JAHNKE, T, NICKLES, J, KAMMER, S, JAGUTZKI, O, et al.(2005). Photo double ionization of helium 100 eV and 450 eV above threshold: I. Linearly polarized light . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 38. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 615-633.

The direct measurement of spectral momentum densities of silicon with high energy (e, 2e) spectroscopy @article{e66d049e90634fc0b0670cd2dd67f6a1, title = "The direct measurement of spectral momentum densities of silicon with high energy (e, 2e) spectroscopy", abstract = "Electron momentum spectroscopy is a coincidence technique that measures the spectral momentum density of matter. In this paper we outline the theoretical framework underlying these measurements, give a description of the spectrometer, and show in detail the information this technique can provide for the prototypical material silicon. We present results for single crystals as well as amorphous samples, describe the influence that diffraction and inelastic multiple scattering have on these measurements. The results are compared with full-potential linear-muffin-tin-orbital (FP-LMTO) calculations (for dispersion), and many-body calculations (for line shapes).", keywords = "Band structure, Electron momentum spectroscopy, Silicon, Spectral function", author = "C. Bowles and Kheifets, \{A. S.\} and Sashin, \{V. A.\} and M. Vos and E. Weigold", year = "2004", month = dec, doi = "10.1016/j.elspec.2004.05.006", language = "English", volume = "141", pages = "95--104", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", number = "2-3", } . Journal of Electron Spectroscopy and Related Phenomena.

Experimental observation of initial-state effects in photo-double-ionization of Ne 2s @article{fb52acf2c42848c6aa0bf0b1b59458b8, title = "Experimental observation of initial-state effects in photo-double-ionization of Ne 2s", abstract = "The triple-differential cross-sections (TDCS) of the He 1s 2 and Ne 2s 2 shells at the same excess energy above the threshold in the equal energy sharing conditions were investigated. The symmetries of both the residual ion and electron pair in the final state, 1S e and 1P 0, as well as the kinetic energy of the ejected electrons were found to be the same. It was observed that the shape of the Ne TDCS displays differences can be explained by the intershell ground-state correlation in Ne as supported by convergent close coupling (CCC) calculations with He-like final state and two different Ne ground states. The results show that the Ne TDCS are qualitatively different from the He ones.", author = "P. Bolognesi and R. Flammini and A. Kheifets and I. Bray and L. Avaldi", year = "2004", month = dec, doi = "10.1103/PhysRevA.70.062715", language = "English", volume = "70", pages = "062715--1--062715--6", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Probing the spectral densities over the full three-dimensional momentum space @article{4de64e7cd92c4e4d81e7f9781ce99abc, title = "Probing the spectral densities over the full three-dimensional momentum space", abstract = "Electron momentum spectroscopy is often used to determine the spectral function of materials. It relies on the determination of the scattering angle of electrons with extremely high precision. In practice, it is important to calibrate these angles, and hence the momentum scales. Here we describe a method to do so and show how minor misalignments affect the measured momentum densities of Li2O. Using the same procedure we further calibrated the momentum scale by measuring the spectral momentum density along a Brillouin zone boundary of a Si single crystal.", keywords = "A. Oxides, A. Semiconductors, A. Thinfilms, D. Electronic structure", author = "M. Vos and Sashin, \{V. A.\} and C. Bowles and Kheifets, \{A. S.\} and E. Weigold", year = "2004", month = dec, doi = "10.1016/j.jpcs.2004.08.017", language = "English", volume = "65", pages = "2035--2039", journal = "Journal of Physics and Chemistry of Solids", issn = "0022-3697", publisher = "Elsevier Ltd.", number = "12", } . Journal of Physics and Chemistry of Solids.

Electronic structure of copper studied by electron momentum spectroscopy @article{25c26d85df274bfeb815601bcbe269a7, title = "Electronic structure of copper studied by electron momentum spectroscopy", abstract = "We present electron momentum spectroscopy measurements of the electronic structure of copper single crystals. Generally, good agreement was found with the band dispersion as measured by photoemission. The energy-resolved momentum densities are quite anisotropic. Observed diffraction effects can be disentangled in first order, and the experiment compares well to calculated momentum density. Deviations of the Fermi surface from spherical symmetry are resolved by this scattering experiment. Many-body effects cause lifetime broadening of the quasiparticle peak and a smooth tail extending to higher binding energies, but no clear satellite structures were found.", author = "M. Vos and Kheifets, \{A. S.\} and C. Bowles and C. Chen and E. Weigold and F. Aryasetiawan", year = "2004", month = nov, doi = "10.1103/PhysRevB.70.205111", language = "English", volume = "70", pages = "205111--1--205111--11", journal = "Physical Review B-Condensed Matter", issn = "0163-1829", publisher = "American Institute of Physics", number = "20", } . Physical Review B-Condensed Matter.

Electronic band structure of calcium oxide @article{28dbf72be2024c54aa50678e4abaa627, title = "Electronic band structure of calcium oxide", abstract = "We employed electron momentum spectroscopy (EMS) to measure the bulk electronic structure of calcium oxide. We extracted the electron momentum density (EMD), density of occupied states (DOS), band dispersions, bandwidths and intervalence bandgaps from the data. The results are compared with calculations based on the full potential linear muffin-tin orbital(FP-LMTO) approximation. While the bandwidths of 0.6±0.2 and 1.2±0.1 eV for the s- and p-bands, respectively, and their dispersions agree well with the LMTO calculation, the relative intensity of the two bands is at odds with the theory. The measured intervalence bandgap at the Γ-point of 16.5±0.2 eV is larger by 2.1 eV than that from the LMTO calculation. The experimental bandwidth of the Ca 3p semi-core level of 0.7±0.1 eV agrees with the LMTO prediction. The measured bandgap between this level and the s-band is 3.6±0.2 eV. The Ca 3s-3p level splitting is in excellent agreement with the literature.", keywords = "Alkaline earth metals, Electron momentum spectroscopy, Electron-solid scattering and transition-inelastic", author = "Bolorizadeh, \{M. A.\} and Sashin, \{V. A.\} and Kheifets, \{A. S.\} and Ford, \{M. J.\}", year = "2004", month = oct, doi = "10.1016/j.elspec.2004.04.004", language = "English", volume = "141", pages = "27--38", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", number = "1", } . Journal of Electron Spectroscopy and Related Phenomena.

Complete photo-fragmentation of the deuterium molecule @article{12cbb844eb7140a7a581df9a8bcaa443, title = "Complete photo-fragmentation of the deuterium molecule", abstract = "All properties of molecules - from binding and excitation energies to their geometry - are determined by the highly correlated initial-state wavefunction of the electrons and nuclei. Details of these correlations can be revealed by studying the break-up of these systems into their constituents. The fragmentation might be initiated by the absorption of a single photon 1-6, by collision with a charged particle7,8 or by exposure to a strong laser pulse9,10: if the interaction causing the excitation is sufficiently understood, the fragmentation process can then be used as a tool to investigate the bound initial state11,12. The interaction and resulting fragment motions therefore pose formidable challenges to quantum theory13,15. Here we report the coincident measurement of the momenta of both nuclei and both electrons from the single-plioton-induced fragmentation of the deuterium molecule. The results reveal that the correlated motion of the electrons is strongly dependent on the inter-nuclear separation in the molecular ground state at the instant of photon absorption.", author = "T. Weber and Czasch, \{A. O.\} and O. Jagutzki and M{\"u}ller, \{A. K.\} and V. Mergel and A. Kheifets and E. Rotenberg and G. Meigs and Proir, \{M. H.\} and S. Daveau and A. Landers and Cocke, \{C. L.\} and T. Oslpov and \{D{\'i}ez Mui{\~n}o\}, R. and H. Schmidt-B{\"o}cking and R. D{\"o}rner", year = "2004", month = sep, day = "23", doi = "10.1038/nature02839", language = "English", volume = "431", pages = "437--440", journal = "Nature", issn = "0028-0836", publisher = "Nature Research", number = "7007", } . Nature.

Measurement of the electronic structure of crystalline silicon by electron momentum spectroscopy @article{6e913318aa3f4ec7b84beba888f06c84, title = "Measurement of the electronic structure of crystalline silicon by electron momentum spectroscopy", abstract = "Electron momentum spectroscopy (EMS) is a scattering experiment that determines the spectral function of a sample, i.e. the density of electrons as a function of binding energy and momentum. Here, it is used to study the spectral function of silicon single crystals in the extended zone scheme. Two symmetry directions and four intermediate directions are measured. The relation between the band index and the main observed momentum component is discussed. The observed peak shapes are compared with many-body calculations based on the cumulant expansion scheme. The dispersion is described well, but peak shapes agree with many-body theory only on a semi-quantitative level.", keywords = "Band index, Electron correlation, Electron momentum spectroscopy, Many body theory, Silicon, Spectral function", author = "M. Vos and C. Bowles and Kheifets, \{A. S.\} and Sashin, \{V. A.\} and E. Weigold and F. Aryasetiawan", year = "2004", month = jul, doi = "10.1016/j.elspec.2004.02.051", language = "English", volume = "137-140", pages = "629--632", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", number = "SPEC. ISS.", } . Journal of Electron Spectroscopy and Related Phenomena.

Many-particle dynamics in atomic and molecular physics investigated with the COLTRIMS-technique @article{162f69c4b7b84b86a7bcaaae59370278, title = "Many-particle dynamics in atomic and molecular physics investigated with the COLTRIMS-technique: New insight into e-e- correlation", author = "H. Schmidt-B{\"o}cking and R. D{\"o}rner and O. Jagutzki and T. Jahnke and V. Mergel and Schmidt, \{L. Ph H.\} and Th Weber and A. Czasch and Ch Wimmer and M. Hattass and A. Knapp and M. Sch{\"o}ffler and Cocke, \{C. L.\} and M. Prior and A. Kheifets and E. Weigold and F. Afaneh", year = "2004", month = jun, day = "14", doi = "10.1016/j.nuclphysa.2004.03.093", language = "English", volume = "737", pages = "306--313", journal = "Nuclear Physics A", issn = "0375-9474", publisher = "Elsevier B.V.", number = "SUPPL.", } . Nuclear Physics A.

Convergent calculations of double ionization of helium @article{e306a598e5d7417fb175d4b8bbc7ace6, title = "Convergent calculations of double ionization of helium: From (γ,2e) to (e,3e) processes", abstract = "The convergent close-coupling (CCC) method was used to calculate the double ionization of helium from (γ,2e) to (e,3e) processes. It was observed that in both cases the initial and final atomic states are three-body problems of the He2+ nucleus interacting with the two slow electrons. It was shown that the application of the CCC method to (e,3e) process under the kinematical conditions is straightforward and expected to produce results as accurate as those for (γ,2e). The absolute relations between the (γ,2e) and (e,3e) calculations were checked and were found to be consistent.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2004", month = may, doi = "10.1103/PhysRevA.69.050701", language = "English", volume = "69", pages = "050701--1--050701--4", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5 A", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Fully differential cross sections for photo-double-ionization of D 2 @article{a7b30c5766fe4b7daf961088c59942e3, title = "Fully differential cross sections for photo-double-ionization of D 2", abstract = "The four-body fragmentation of D2 molecule which was followed by single photon absorption was analyzed. The relaxation of one of selection rules valid for He photo-double-ionization and strong dependence of electron angular distribution on orientation of molecular axis were observed. The fully differential cross sections (FDCS) indicated that angular correlation pattern was formed by electron-electron correlation in final state. The model in which pair of photoionization amplitudes was also introduced for light polarization parallel and perpendicular to molecular axis.", author = "Th Weber and A. Czasch and O. Jagutzki and A. M{\"u}ller and V. Mergel and A. Kheifets and J. Feagin and E. Rotenberg and G. Meigs and Prior, \{M. H.\} and S. Daveau and Landers, \{A. L.\} and Cocke, \{C. L.\} and T. Osipov and H. Schmidt-B{\"o}cking and R. D{\"o}rner", year = "2004", month = apr, day = "23", doi = "10.1103/PhysRevLett.92.163001", language = "English", volume = "92", pages = "163001--1--163001--4", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "16", } . Physical Review Letters.

Spectral momentum densities in matter determined by electron scattering @article{377a9f1eecc341e78d578b8534de5df9, title = "Spectral momentum densities in matter determined by electron scattering", abstract = "In electron momentum spectroscopy (EMS), an incoming energetic electron (50 keV in this work) ionizes the target and the scattered and ejected electrons are detected in coincidence (at energies near 25 keV). From the energy and momentum of the detected particles, the energy ω and momentum q transferred to the target can be inferred. The observed intensity distribution I(ω, q) is proportional to the spectral momentum density of the target and hence provides a direct challenge to many-body theoretical descriptions of condensed matter. This is illustrated by comparing some many-body calculations with EMS measurements on graphite and polycrystalline aluminium.", author = "Erich Weigold and Kheifets, \{Anatoli S.\} and Sashin, \{Vladimir A.\} and Maarten Vos", year = "2004", month = mar, doi = "10.1107/S0108767303029349", language = "English", volume = "60", pages = "104--110", journal = "Acta Crystallographica Section A: Foundations of Crystallography", issn = "0108-7673", publisher = "International Union of Crystallography", number = "2", } . Acta Crystallographica Section A: Foundations of Crystallography.

Second-order Born model for two-electron atomic ionization by fast charged-particle impact @article{3b0828dfd65c43fe870f9af4ad3e2f39, title = "Second-order Born model for two-electron atomic ionization by fast charged-particle impact", abstract = "The second-order Born theoretical model developed for describing simultaneous ionization excitation and double ionization of a two-electron atomic shell by a fast charged-particle impact, was discussed. The model measured the projectile-target interaction to the second order, whereas the interaction of the two target electrons ejected into continuum was treated nonperturbatively by the convergent close-coupling (CCC) method. The model was used to describe two-electron ionization processes with large projectile velocity, small momentum transfer, and small to intermediate energy of the ejected electrons. The model was also applied to ionization excitation and double ionization of He by electron and positron impact in kinematics.", author = "Kheifets, \{A. S.\}", year = "2004", month = mar, doi = "10.1103/PhysRevA.69.032712", language = "English", volume = "69", pages = "032712--1--032712--12", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "3", } . Physical Review A - Atomic, Molecular, and Optical Physics.

C. Bowles, A.S. Kheifets, V.A. Sashin, M. Vos, E. Weigold (2004). The direct measurement of spectral momentum densities of silicon with high energy spectroscopy . Journal of Electron Spectroscopy and Related Phenomena.

M. Vos, A. S. Kheifets, C. Bowles, C. Chen, E. Weigold, F. Aryasetiawan (2004). Electronic structure of copper studied by electron momentum spectroscopy . Physical Review B.

Weber, T, Czasch, AO, Jagutzki, O, M&#252;ller, AK, Mergel, V, Kheifets, A, Rotenberg, E, Meigs, G, Prior, MH, Daveau, S, et al. (2004). Complete photo-fragmentation of the deuterium molecule . Nature Reviews Bioengineering.

KHEIFETS, AS(2004). Second-order Born model for two-electron atomic ionization by fast charged-particle impact . PHYSICAL REVIEW A. 69. (3).

WEBER, T, CZASCH, AO, JAGUTZKI, O, MULLER, AK, MERGEL, V, KHEIFETS, A, ROTENBERG, E, MEIGS, G, PRIOR, MH, DAVEAU, S, et al.(2004). Complete photo-fragmentation of the deuterium molecule . NATURE. 431. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 437-440.

A. S. Kheifets (2004). Second-order Born model for two-electron atomic ionization by fast charged-particle impact . Physical Review A.

BOLOGNESI, P, AVALDI, L, BRAY, I, CAMILLONI, R, CORENO, M, KAZANSKY, K, KHEIFETS, AS, MALEGAT, L, SELLES, P, TURRI, G, et al.(2004). The photodouble ionisation of helium and heavier rare gases . PHYSICA SCRIPTA. T110. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 62-67.

M.A. Bolorizadeh, V.A. Sashin, A.S. Kheifets, M.J. Ford (2004). Electronic band structure of calcium oxide . Journal of Electron Spectroscopy and Related Phenomena.

Weber, T, Czasch, A, Jagutzki, O, M&#252;ller, A, Mergel, V, Kheifets, A, Feagin, J, Rotenberg, E, Meigs, G, Prior, MH, et al. (2004). Fully differential cross sections for photo-double-ionization of D₂ - art. no. 163001 . Physical Review Letters.

WEBER, T, CZASCH, A, JAGUTZKI, O, MULLER, A, MERGEL, V, KHEIFETS, A, FEAGIN, J, ROTENBERG, E, MEIGS, G, PRIOR, MH, et al.(2004). Fully differential cross sections for photo-double-ionization of D-2 . PHYSICAL REVIEW LETTERS. 92. (16).

A. S. Kheifets, Igor Bray (2004). Convergent calculations of double ionization of helium: From <math display="inline"> <mrow> <mrow> <mo>(</mo> <mrow> <mi>γ</mi> <mo>,</mo> <mn>2</mn> <mi>e</mi> </mrow> <mo>)</mo> </mrow> </mrow> </math> to <math display="inline"> <mrow> <mrow> <mo>(</mo> <mrow> <mi>e</mi> <mo>,</mo> <mn>3</mn> <mi>e</mi> </mrow> <mo>)</mo> </mrow> </mrow> </math> processes . Physical Review A.

Bolognesi, P, Flammini, R, Kheifets, A, Bray, I, Avaldi, L (2004). Experimental observation of initial-state effects in photo-double-ionization of Ne 2<i>s</i> -: art. no. 062715 . Physical Review A.

Bolognesi, P., Avaldi, L., Bray, I., Camilloni, R., Coreno, M., Kazansky, K., Kheifets, A. S., Malegat, L., Selles, P., Turri, G., et al. (2004). The photodouble ionisation of helium and heavier rare gases . Physica Scripta.

BOLORIZADEH, MA, SASHIN, VA, KHEIFETS, AS, FORD, MJ(2004). Electronic band structure of calcium oxide . JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. 141. (1). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 27-38.

BOWLES, C, KHEIFETS, AS, SASHIN, VA, VOS, M, WEIGOLD, E(2004). The direct measurement of spectral momentum densities of silicon with high energy (e, 2e) spectroscopy . JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. 141. (2-3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 95-104.

P. Bolognesi, L. Avaldi, I. Bray, R. Camilloni, M. Coreno, K. Kazansky, A. S. Kheifets, L. Malegat, P. Selles, G. Turri, et al.(2004). The photodouble ionisation of helium and heavier rare gases . Physica Scripta. T110. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 62--67. Institute of Physics

BOLOGNESI, P, FLAMMINI, R, KHEIFETS, A, BRAY, I, AVALDI, L(2004). Experimental observation of initial-state effects in photo-double-ionization of Ne 2s . PHYSICAL REVIEW A. 70. (6).

KHEIFETS, AS, BRAY, I(2004). Convergent calculations of double ionization of helium: From (gamma,2e) to (e,3e) processes . PHYSICAL REVIEW A. 69. (5).

VOS, M, KHEIFETS, AS, BOWLES, C, CHEN, C, WEIGOLD, E, ARYASETIAWAN, F(2004). Electronic structure of copper studied by electron momentum spectroscopy . PHYSICAL REVIEW B. 70. (20).

Spectral properties of quasiparticles in silicon @article{96a38f97cf114d65b483b3c797735d4f, title = "Spectral properties of quasiparticles in silicon: A test of many-body theory", abstract = "The spectral function A(q, ω) of silicon has been measured along a number of symmetry directions using high-energy high-resolution electron momentum spectroscopy. It is compared with first-principles calculations based on the interacting one-electron Green{\textquoteright}s function which is evaluated in the GW and the cumulant expansion approximations. Positions of the quasiparticle peaks (dispersion), their widths (lifetimes), and the extensive satellite structures are measured over a broad range of energies and momenta. The band dispersions are well described by both calculations, but the satellite predicted by the GW calculation is not observed. Unlike the GW calculation, the cumulant expansion calculation gives a significantly better description of the shape and momentum dependence of the satellite structure, presenting a promising approach for studying high-energy excitations.", author = "Kheifets, \{A. S.\} and Sashin, \{V. A.\} and M. Vos and E. Weigold and F. Aryasetiawan", year = "2003", month = dec, day = "22", doi = "10.1103/PhysRevB.68.233205", language = "English", volume = "68", journal = "Physical Review B - Condensed Matter and Materials Physics", issn = "1098-0121", publisher = "American Physical Society", number = "23", } . Physical Review B - Condensed Matter and Materials Physics.

Influence of electron diffraction on measured energy-resolved momentum densities in single-crystalline silicon @article{9b3a726d047a473fa96a0fb7f98a8180, title = "Influence of electron diffraction on measured energy-resolved momentum densities in single-crystalline silicon", abstract = "Electron momentum spectroscopy is used to determine the spectral function of silicon single crystals. In these experiments 50 keV electrons impinge on a self-supporting thin silicon film and scattered and ejected electrons emerging from this sample with energies near 25 keV are detected in coincidence. Diffraction effects are present that give rise to additional structures in the measured spectral momentum densities. Spectra for a specific momentum value can be obtained at different orientations of the crystal relative to the analysers. By comparing these spectra for which the measured momentum density is the same, but the diffraction conditions of the incoming and outgoing electron trajectories differ, one can distinguish between features due to diffraction of the incoming and/or outgoing electrons, and those due to the electronic structure of the target itself.", keywords = "C. Electron, Diffraction", author = "M. Vos and Kheifets, \{A. S.\} and Sashin, \{V. A.\} and E. Weigold", year = "2003", month = dec, doi = "10.1016/j.jpcs.2003.08.004", language = "English", volume = "64", pages = "2507--2515", journal = "Journal of Physics and Chemistry of Solids", issn = "0022-3697", publisher = "Elsevier Ltd.", number = "12", } . Journal of Physics and Chemistry of Solids.

Dynamics of ionization processes studied with the COLTRIMS method - New insight into e-e correlation @article{d6f74abbe1f642798d099654b42d9e92, title = "Dynamics of ionization processes studied with the COLTRIMS method - New insight into e-e correlation", abstract = "Many particle dynamics in atomic and molecular physics has been investigated by using the COLTRIMS method. The method and its power is discussed. The COLTRIMS technique visualizes many-particle fragmentation processes in the eV and sub milli-eV regime and reveals like the bubble chamber the complete momentum pattern in atomic and molecular particles reactions. Complete differential cross sections in momentum space have been measured for the transfer ionization channel in fast four-body (p+He→H°+He2++e) collisions. The correlated kinematical transfer ionization channel has been used to probe the highly correlated contributions to the asymptotic parts (high momenta and large nuclear impact parameters) of the He ground-state momentum wave function. In this reaction, one electron with selected initial momentum (2.5-7.5a.u.) in the He ground state is kinematically captured by the proton (tunneling through the two-center barrier). The measured three-particle final-state momentum distributions show well-structured patterns, which reflect special features of the three-particle initial-state momentum wave function.", author = "H. Schmidt-B{\"o}cking and V. Mergel and L. Schmidt and R. D{\"o}rner and O. Jagutzki and K. Ullmann and T. Weber and L{\"u}dde, \{H. J.\} and E. Weigold and Kheifets, \{A. S.\}", year = "2003", month = sep, day = "1", doi = "10.1016/S0969-806X(03)00254-8", language = "English", volume = "68", pages = "41--50", journal = "Radiation Physics and Chemistry", issn = "0969-806X", publisher = "Elsevier Ltd.", number = "1-2", } . Radiation Physics and Chemistry.

A procedure to extract the complex amplitudes of He photodouble ionization from experimental data @article{f7db9abd03804c8281821411f0fc9c84, title = "A procedure to extract the complex amplitudes of He photodouble ionization from experimental data", abstract = "A procedure to extract the complex amplitudes of He photodouble ionization from experimental data was discussed. The results for an experiment performed in complementary kinematics at E = 40 eV were presented. The comparison of results with the predictions of the convergent close coupling and hyperspherical R-matrix with semiclassical outgoing wave theories was also analyzed.", author = "P. Bolognesi and Kheifets, \{A. S.\} and I. Bray and L. Malegat and P. Selles and Kazansky, \{A. K.\} and L. Avaldi", year = "2003", month = aug, day = "28", doi = "10.1088/0953-4075/36/16/102", language = "English", volume = "36", pages = "L241--L247", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "16", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Double shake-off model for the triple photoionization of beryllium @article{532ef9aaa29b4b1ea455c4168193800e, title = "Double shake-off model for the triple photoionization of beryllium", abstract = "We propose a model for the triple photoionization of Be in which a core 1s electron absorbs the photon γ + 1s22s2 Be → ε1p + 1s2s2 Be+ and the valence 2s2 electrons are shaken off into continuum due to the sudden change of the core potential. We decompose the double shake-off amplitude into a single shake-off 2s2 → nsεs and a subsequent electron impact ionization of the doubly charged Be2+ ion εs + 1sns Be2+ → ε2l + ε3l + 1s Be3+. The latter process is described by the T-matrix of inelastic electron scattering on the 'semi-hollow' 1sns Be2+ ion in the monopole singlet channel. The convergent close-coupling method is used to evaluate the T-matrix.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2003", month = jul, day = "14", doi = "10.1088/0953-4075/36/13/103", language = "English", volume = "36", pages = "L211--L217", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "13", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Appearance and disappearance of the second Born effects in the (e,3e) reaction on He @article{36de623548d74b57a22161988bc69aa2, title = "Appearance and disappearance of the second Born effects in the (e,3e) reaction on He", abstract = "The relative contribution of the first and second Born processes leading to the double ionization of He by electron impact at 500 eV was investigated. In the first Born processes, the projectile interacts with the target only once and ejection of the two target electrons is possible solely due to electron correlations in the target before and after collision. In contrast, in the second Born process, ejection of the two target electrons happens sequentially as a result of two subsequent knock-outs of the projectile on the target. In general, both the first and second Born processes contribute to double ionization of He at an incident energy of 500 eV. However, the second Born contribution is insignificant for ionizing collisions with a large momentum transfer.", author = "A. Dorn and A. Kehifets and Schr{\"o}ter, \{C. D.\} and C. H{\"o}hr and G. Sakhelashvili and R. Moshammer and J. Lower and J. Ullrich", year = "2003", month = jul, language = "English", volume = "68", pages = "012715/1--012715/4", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "1", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Electronic band structure of beryllium oxide @article{b618645aa02445ad9ef8acc2fd50f318, title = "Electronic band structure of beryllium oxide", abstract = "Atomic and Molecular Physics Laboratories, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200, Australia. The energy-momentum resolved valence band structure of beryllium oxide has been measured by electron momentum spectroscopy (EMS). Band dispersions, bandwidths and intervalence bandgap, electron momentum density (EMD) and density of occupied states have been extracted from the EMS data. The experimental results are compared with band structure calculations performed within the full potential linear muffin-tin orbital approximation. Our experimental bandwidths of 2.1 ± 0.2 and 4.8 ± 0.3 eV for the oxygen s and p bands, respectively, are in accord with theoretical predictions, as is the s-band EMD after background subtraction. Contrary to the calculations, however, the measured p-band EMD shows large intensity at the Γ point. The measured full valence bandwidth of 19.4 ± 0.3 eV is at least 1.4 eV larger than the theory. The experiment also finds a significantly higher value for the p-to-s-band EMD ratio in a broad momentum range compared to the theory.", author = "Sashin, \{V. A.\} and Bolorizadeh, \{M. A.\} and Kheifets, \{A. S.\} and Ford, \{M. J.\}", year = "2003", month = jun, day = "4", doi = "10.1088/0953-8984/15/21/306", language = "English", volume = "15", pages = "3567--3581", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "21", } . Journal of Physics Condensed Matter.

Revealing the non-s2 contributions in the momentum wave function of ground-state He @article{8e7d15118aa84bb5a1b6b4b06c6874b6, title = "Revealing the non-s2 contributions in the momentum wave function of ground-state He", abstract = "The correlated Tunneling Transfer Ionization (TuTI) channel in fast 4-body processes p + He → H0 + He2+ +e is utilized to probe the highly correlated asymptotic parts of the He ground-state momentum space wave function. In this reaction, predominantly at large nuclear impact parameters, one electron in the He ground state is captured by the proton by tunneling through the two-center barrier when electron and proton velocity vectors resonantly match. The measured 3-particle final-state momentum distributions show characteristic features that we trace back to the highly correlated non-s2 components of the He ground-state momentum wave function. This conclusion is supported by a simple heuristic model.", author = "H. Schmidt-B{\"o}cking and V. Mergel and R. D{\"o}rner and Cocke, \{C. L.\} and O. Jagutzki and L. Schmidt and Th Weber and L{\"u}dde, \{H. J.\} and E. Weigold and J. Berakdar and H. Cederquist and Schmidt, \{H. T.\} and R. Schuch and Kheifets, \{A. S.\}", year = "2003", month = may, doi = "10.1209/epl/i2003-00378-5", language = "English", volume = "62", pages = "477--483", journal = "Europhysics Letters", issn = "0295-5075", publisher = "IOP Publishing Ltd.", number = "4", } . Europhysics Letters.

High-resolution high-energy (e,2e) spectroscopy of metal oxides @article{3d6453c3c8e24e29a663a4ca08635d37, title = "High-resolution high-energy (e,2e) spectroscopy of metal oxides", abstract = "We perform electron momentum spectroscopy studies of a Li2O film using the (e, 2e) spectrometer of the Australian National University. This technique provides a direct observation of the electron motion through measurement of the energy-momentum resolved density. The spectrometer has a symmetric geometry with Incident and outgoing electron energies of 50 keV and 25 keV, respectively. These relatively high energies minimise the effect of multiple scattering on the spectral momentum density. The energy and momentum resolutions are about 1 eV and 0.1 a.u., respectively. We compare the results with calculations performed within the linear muffin-tin orbital approximation. The measured bandwidths of 1.8 ± 0.1 eV and 0.4 ± 0.1 eV for the upper (UVB) and lower (LVB) valence bands, respectively, are In good agreement with the calculation, but the momentum distribution for the UVB deviates strongly from theory. Similarly, the theory predicts correctly the bandwidths in the alkaline-earth metal oxides, BeO, MgO and CaO, except for the UVB in CaO. However, the measured intervalence gap for Li2O is as much as 2.3 eV wider than that of theory. Similar results are also observed for the three other oxides.", author = "Sashin, \{V. A.\} and M. Vos and Kheifets, \{A. S.\} and E. Weigold", year = "2003", language = "English", volume = "172", pages = "79--88", journal = "Institute of Physics Conference Series", issn = "0951-3248", publisher = "IOP Publishing Ltd.", note = "International Conference on Electron and Photon Impact Ionization and Related Topics 2002 ; Conference date: 18-07-2002 Through 20-07-2002", } . Institute of Physics Conference Series.

V A Sashin, M A Bolorizadeh, A S Kheifets, M J Ford (2003). Electronic band structure of beryllium oxide . Journal of Physics: Condensed Matter.

KHEIFETS, AS, BRAY, I(2003). Double shake-off model for the triple photoionization of beryllium . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 36. (13). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L211-L217.

M. Vos, A.S. Kheifets, V.A. Sashin, E. Weigold (2003). Influence of electron diffraction on measured energy-resolved momentum densities in single-crystalline silicon . Journal of Physics and Chemistry of Solids.

Dorn, A, Kheifets, A, Schr&#246;ter, CD, H&#246;hr, C, Sakhelashvili, G, Moshammer, R, Lower, J, Ullrich, J (2003). Appearance and disappearance of the second Born effects in the (<i>e</i>,3<i>e</i>) reaction on He - art. no. 012715 . Physical Review A.

KHEIFETS, AS, SASHIN, VA, VOS, M, WEIGOLD, E, ARYASETIAWAN, F(2003). Spectral properties of quasiparticles in silicon: A test of many-body theory . PHYSICAL REVIEW B. 68. (23).

Schmidt-B&#246;cking, H, Mergel, V, D&#246;rner, R, Cocke, CL, Jagutzki, O, Schmidt, L, Weber, T, L&#252;dde, HJ, Weigold, E, Berakdar, J, et al. (2003). Revealing the non-<i>s</i><SUP>2</SUP> contributions in the momentum wave function of ground-state He . EPL (Europhysics Letters).

BOLOGNESI, P, KHEIFETS, AS, BRAY, I, MALEGAT, L, SELLES, P, KAZANSKY, AK, AVALDI, L(2003). A procedure to extract the complex amplitudes of He photodouble ionization from experimental data . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 36. (16). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L241-L247.

SASHIN, VA, BOLORIZADEH, MA, KHEIFETS, AS, FORD, MJ(2003). Electronic band structure of beryllium oxide . JOURNAL OF PHYSICS-CONDENSED MATTER. 15. (21). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3567-3581.

VOS, M, KHEIFETS, AS, SASHIN, VA, WEIGOLD, E(2003). Influence of electron diffraction on measured energy-resolved momentum densities in single-crystalline silicon . JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS. 64. (12). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2507-2515.

Bolognesi, P, Kheifets, AS, Bray, I, Malegat, L, Selles, P, Kazansky, AK, Avaldi, L (2003). A procedure to extract the complex amplitudes of He photodouble ionization from experimental data . Journal of Physics B: Atomic, Molecular and Optical Physics.

DORN, A, KHEIFETS, A, SCHROTER, CD, HOHR, C, SAKHELASHVILI, G, MOSHAMMER, R, LOWER, J, ULLRICH, J(2003). Appearance and disappearance of the second Born effects in the (e,3e) reaction on He . PHYSICAL REVIEW A. 68. (1).

A. S. Kheifets, V. A. Sashin, M. Vos, E. Weigold, F. Aryasetiawan (2003). Spectral properties of quasiparticles in silicon: A test of many-body theory . Physical Review B.

SCHMIDT-BOCKING, H, MERGEL, V, DORNER, R, COCKE, CL, JAGUTZKI, O, SCHMIDT, L, WEBER, T, LUDDE, HJ, WEIGOLD, E, BERAKDAR, J, et al.(2003). Revealing the non-s(2) contributions in the momentum wave function of ground-state He . EUROPHYSICS LETTERS. 62. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 477-483.

A S Kheifets, Igor Bray (2003). Double shake-off model for the triple photoionization of beryllium . Journal of Physics B: Atomic, Molecular and Optical.

Quantitative measurement of the spectral function of aluminum and lithium by electron momentum spectroscopy @article{958ea8e974fd44dfb5e4b58861bb1ceb, title = "Quantitative measurement of the spectral function of aluminum and lithium by electron momentum spectroscopy", abstract = "We present measurements of the spectral function of aluminum and lithium using high-energy electron momentum spectroscopy. For aluminum the quasiparticle peaks show clear asymmetries and significant satellite intensity that extends over a wide region to larger binding energies. The intensity distribution is not well described by band structure calculations. These data are described only by calculations based on the manybody cumulant expansion scheme. The measured momentum distribution at the Fermi level agrees with the theoretical one within 0.03 a.u. For lithium a bandwidth of 3.0 eV is obtained.", author = "M. Vos and Kheifets, \{A. S.\} and Sashin, \{V. A.\} and E. Weigold and M. Usuda and F. Aryasetiawan", year = "2002", month = oct, day = "15", doi = "10.1103/PhysRevB.66.155414", language = "English", volume = "66", pages = "1554141--15541412", journal = "Physical Review B-Condensed Matter", issn = "0163-1829", publisher = "American Institute of Physics", number = "15", } . Physical Review B-Condensed Matter.

Electrons and photons colliding with atoms @article{2476241e9e1c477fa0da98db5af40bac, title = "Electrons and photons colliding with atoms: Development and application of the convergent close-coupling method", abstract = "The substantial progress that has occurred during the 1990s in the field of electron-atom-collision theory is discussed. We show how a solution of a small-model three-body problem, using the convergent close-coupling method, has led to numerous applications involving real atomic collision systems. Consequently many fundamental electron-atom collision processes are considered as 'solved', and accurate collision data of interest to science and industry have become available. However, we suggest that the present has only just seen the birth of modern atomic collision theory. There are many more important collision problems to be tackled, with guidance coming from experiment being as important as ever.", author = "I. Bray and Fursa, \{D. V.\} and Kheifets, \{A. S.\} and Stelbovics, \{A. T.\}", year = "2002", month = aug, day = "14", doi = "10.1088/0953-4075/35/15/201", language = "English", volume = "35", pages = "R117--R146", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "15", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Mechanisms of photo double ionization of helium by 530 eV photons @article{82dc9cf0afd34df6b1c4c2510eee9424, title = "Mechanisms of photo double ionization of helium by 530 eV photons", abstract = "The theoretical calculations and experimental data of photo double ionization (PDI) of helium at 530 eV photon energy was presented. Asymmetric energy sharing between the photoelectrons and an angular asymmetry parameter β ≅ 2 and β ≅ 0 for the fast and slow electrons was found. The electron angular distributions showed an inelastic electron-electron scattering at an electron energy of 30 eV and a dominance of the shakeoff for 2eV electrons. The data was found to be in aggrement with convergent close-coupling calculations.", author = "A. Knapp and A. Kheifets and I. Bray and Th Weber and Landers, \{A. L.\} and S. Sch{\"o}ssler and T. Jahnke and J. Nickles and S. Kammer and O. Jagutzki and Schmidt, \{L. Ph H.\} and T. Osipov and J. R{\"o}sch and J. R{\"o}sch and Prior, \{M. H.\} and H. Schmidt-B{\"o}cking and Cocke, \{C. L.\} and R. D{\"o}rner", year = "2002", month = jul, day = "15", doi = "10.1103/PhysRevLett.89.033004", language = "English", volume = "89", pages = "330041--330044", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "3", } . Physical Review Letters.

Double photoionization of He at 80 eV excess energy in the equal-energy-sharing condition @article{0b0dc5f0678047958769bd7c394c379a, title = "Double photoionization of He at 80 eV excess energy in the equal-energy-sharing condition", abstract = "The measurements of the triply differential cross section (TDCS) of He in equal-energy-sharing conditions put to E=80 eV was extended. It was shown that an efficient comparison between experiment and theory can be achieved using ag2 instead of the TDCS. Moreover, the Gaussian Ansatz appears to be a suitable representation of the ag amplitude up to this energy.", author = "G. Turri and L. Avaldi and P. Bolognesi and R. Camilloni and M. Coreno and J. Berakdar and Kheifets, \{A. S.\} and G. Stefani", year = "2002", month = mar, doi = "10.1103/PhysRevA.65.034702", language = "English", volume = "65", pages = "1--4", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "3", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Symmetrized amplitudes of the helium-atom double photoionization @article{b120047804e64e70970b2c5e6cdaf94d, title = "Symmetrized amplitudes of the helium-atom double photoionization", abstract = "A series of convergent close-coupling (CCC) calculations of the symmetrized amplitudes of the helium atom double photoionization (DPI) were carried out at several fixed excess energies and varying energy ratios. Gaussian fits obtained directly from the theory were provided. Utility of the 4P Gaussian parametrization was illustrated in the case of 40 eV excess energy with E1=35 eV and E2=5 eV. The resulting data were analyzed in detail.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2002", month = feb, doi = "10.1103/PhysRevA.65.022708", language = "English", volume = "65", pages = "22708/1--22708/8", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "2", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Comparative theoretical study of (e, 3e) on helium @article{d6d8ff0296ac4b73beddd2d23034b86b, title = "Comparative theoretical study of (e, 3e) on helium: Coulomb-waves versus close-coupling approach", abstract = "We discuss common features and differences in the fully differential cross sections (FDCS) for the electron-impact double ionization of He evaluated using the convergent close-coupling (CCC) method and various methods that utilize the three-body Coulomb wavefunctions (3C and C4FS). The calculations are restricted to the first Born approximation with respect to the interaction of the fast projectile with the target. In contrast to the similar (γ, 2e) reactions, where predictions of all the above theories qualitatively agree, there is a systematic difference between the FDCS calculated in the CCC and the 3C-type theories which is amplified as the momentum transfer from the projectile to the target increases. We argue that this fact is an indication that the P partial wave of a two-electron final state wavefunction is well described by the 3C model, but higher partial waves are poorly treated.", author = "Kheifets, \{A. S.\} and Igor Bray and J. Berakdar and \{Dal Cappello\}, C.", year = "2002", month = jan, day = "14", doi = "10.1088/0953-4075/35/1/103", language = "English", volume = "35", pages = "L15--L21", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "1", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Frozen-core model of the double photoionization of beryllium @article{6a0f85317aa640b4ab56f8e47dffa4ce, title = "Frozen-core model of the double photoionization of beryllium", abstract = "The integrated and fully differential cross sections of the DPI (double photoionization) of beryllium (Be) in the frozen-core approximation were presented. The photon-energy dependence of the total ionization excitation and the double ionization cross sections in Be resembled that of helium (He). Various singly and doubly ionized channels were represented by a near-complete set of negative and positive energy pseudostates.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2002", month = jan, doi = "10.1103/PhysRevA.65.012710", language = "English", volume = "65", pages = "127101--127106", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "1", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Dorn, A, Kheifets, A, Schr&#246;ter, CD, Najjari, B, H&#246;hr, C, Moshammer, R, Ullrich, J (2002). Double ionization of helium by electron impact in the impulsive regime - art. no. 032709 . Physical Review A.

A. S. Kheifets, Igor Bray (2002). Frozen-core model of the double photoionization of beryllium . Physical Review A.

Kheifets, AS, Bray, I, Berakdar, J, Dal Cappello, C (2002). Comparative theoretical study of (e, 3e) on helium: Coulomb-waves versus close-coupling approach . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS, BRAY, I(2002). Frozen-core model of the double photoionization of beryllium . PHYSICAL REVIEW A. 65. (1).

DORN, A, KHEIFETS, A, SCHROTER, CD, NAJJARI, B, HOHR, C, MOSHAMMER, R, ULLRICH, J(2002). Double ionization of helium by electron impact in the impulsive regime . PHYSICAL REVIEW A. 65. (3).

KHEIFETS, AS, BRAY, I(2002). Symmetrized amplitudes of the helium-atom double photoionization . PHYSICAL REVIEW A. 65. (2).

M. Vos, A.S. Kheifets, V.A. Sashin, E. Weigold, M. Usuda, F. Aryasetiawan (2002). Quantitative measurement of the spectral function of aluminum and lithium by electron momentum spectroscopy . Physical Review B.

Turri, G, Avaldi, L, Bolognesi, P, Camilloni, R, Coreno, M, Berakdar, J, Kheifets, AS, Stefani, G (2002). Double photoionization of He at 80 eV excess energy in the equal-energy-sharing condition - art. no. 034702 . Physical Review A.

BRAY, I, FURSA, DV, KHEIFETS, AS, STELBOVICS, AT(2002). Electrons and photons colliding with atoms development and application of the convergent close-coupling method . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 35. (15). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString R117-R146.

VOS, M, KHEIFETS, AS, SASHIN, VA, WEIGOLD, E, USUDA, M, ARYASETIAWAN, F(2002). Quantitative measurement of the spectral function of aluminum and lithium by electron momentum spectroscopy . PHYSICAL REVIEW B. 66. (15).

Knapp, A, Kheifets, A, Bray, I, Weber, T, Landers, AL, Sch&#246;ssler, S, Jahnke, T, Nickles, J, Kammer, S, Jagutzki, O, et al. (2002). Mechanisms of photo double ionization of helium by 530 eV photons - art. no. 033004 . Physical Review Letters.

A. S. Kheifets, Igor Bray (2002). Symmetrized amplitudes of the helium-atom double photoionization . Physical Review A.

TURRI, G, AVALDI, L, BOLOGNESI, P, CAMILLONI, R, CORENO, M, BERAKDAR, J, KHEIFETS, AS, STEFANI, G(2002). Double photoionization of He at 80 eV excess energy in the equal-energy-sharing condition . PHYSICAL REVIEW A. 65. (3).

Anatoli Kheifets, Alexander R Dorn, C D Schroter, B Najjari, C Hohr, R Moshammer, Joachim Ullrich(2002). Double ionization of helium by electron impact in the impulsive regime . Physical Review A: Atomic, Molecular and Optical Physics. 65. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 032709--1--8. American Physical Society

KHEIFETS, AS, BRAY, I, BERAKDAR, J, DAL CAPPELLO, C(2002). Comparative theoretical study of (e, 3e) on helium: Coulomb-waves versus close-coupling approach . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 35. (1). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L15-L21.

KNAPP, A, KHEIFETS, A, BRAY, I, WEBER, T, LANDERS, AL, SCHOSSLER, S, JAHNKE, T, NICKLES, J, KAMMER, S, JAGUTZKI, O, et al.(2002). Mechanisms of photo double ionization of helium by 530 eV photons . PHYSICAL REVIEW LETTERS. 89. (3).

I Bray, D V Fursa, A S Kheifets, A T Stelbovics (2002). Electrons and photons colliding with atoms development and application of the convergent close-coupling method . Journal of Physics B: Atomic, Molecular and Optical Physics.

The spectral momentum density of aluminum measured by electron momentum spectroscopy @article{4d44188b753c4a9fa6c1e2fab7cc3f87, title = "The spectral momentum density of aluminum measured by electron momentum spectroscopy", abstract = "Electron momentum spectroscopy is a tool ideally suited for the study of energy-resolved momentum densities. Here we present new data from a high-energy EMS experiment using 50 keV incoming and 25 keV outgoing electrons. Both the measured energy distributions and the measured momentum distributions are affected by multiple scattering. However, after correcting for these effects, neither distribution can be fully understood using electronic structure calculations that take electron-electron correlation into account only on a mean-field level.", author = "M. Vos and Kheifets, \{A. S.\} and E. Weigold", year = "2001", month = dec, doi = "10.1016/S0022-3697(01)00180-9", language = "English", volume = "62", pages = "2215--2221", journal = "Journal of Physics and Chemistry of Solids", issn = "0022-3697", publisher = "Elsevier Ltd.", number = "12", } . Journal of Physics and Chemistry of Solids.

Helium (γ, 2e) triple differential cross sections at an excess energy of 60 eV @article{69ce3c3eb3d84cb48001fa18172a2479, title = "Helium (γ, 2e) triple differential cross sections at an excess energy of 60 eV", abstract = "(γ, 2e) triple differential cross sections are presented for helium at 60 eV above the photodouble ionization threshold with energy-sharing ratios (R = E2/E1) for the two ejected electrons of R = 1, 5 and 11. The measurements were taken using a toroidal spectrometer and linearly polarized light from an undulator beamline (SU6) at the Super-ACO storage ring. Good agreement is found with TDCSs obtained by the CCC method and by the length gauge of 3C theory.", author = "C. Dawson and S. Cvejanovic and Seccombe, \{D. P.\} and Reddish, \{T. J.\} and F. Maulbetsch and A. Huetz and J. Mazeau and Kheifets, \{A. S.\}", year = "2001", month = aug, day = "28", doi = "10.1088/0953-4075/34/16/104", language = "English", volume = "34", pages = "L525--L533", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "16", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Complementary TDCS for the photo-double ionization of He at 40 eV above the threshold in unequal energy-sharing conditions @article{5b5355dbbd9e488ebcecd8f8ab928dbb, title = "Complementary TDCS for the photo-double ionization of He at 40 eV above the threshold in unequal energy-sharing conditions", abstract = "Photo-double ionization (PDI) of helium at 40 eV above the threshold has been studied for unequal energy sharing in the complementary kinematics obtained in two measurements by the interchange of the kinetic energies of two photoelectrons. Triple differential cross sections (TDCS) of Helium excess energy were measured at unequal energy sharing for the complementary cases. TDCS measurements show that the excess energy of 40 eV the motion of the two photoelectrons was more correlated than expected solely on the basis of the measurements and calculations of the less-differential cross sections. This showed the transition form the highly correlated motion, threshold region to a completely uncorrelated one.", author = "P. Bolognesi and R. Camilloni and M. Coreno and G. Turri and J. Berakdar and Kheifets, \{A. S.\} and L. Avaldi", year = "2001", month = aug, day = "14", doi = "10.1088/0953-4075/34/15/321", language = "English", volume = "34", pages = "3193--3203", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "15", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Complete experiments for the double ionization of He @article{bcc0d95ef6944bba925c8388fe7e0f58, title = "Complete experiments for the double ionization of He: (e, 3e) cross sections at 1 keV impact energy and small momentum transfer", abstract = "The reaction cross sections and momentum transfer of the electrons produced in electron-impact double ionization of He were measured. The energy and linear momentum conservation laws were used to obtain the kinematical variables of the particles involved in ionization. The experimental data on the (e,3e) fully resolved cross sections were analyzed in different angular modes to compare it with the state-of-art calculations. The analysis suggested that the optical limit depended on incident energy and the amount of momentum transfer as well as on the emission direction of slow ejected electrons in double ionization of He.", author = "A. Lahmam-Bennani and A. Duguet and Gaboriaud, \{M. N.\} and I. Taouil and M. Lecas and A. Kheifets and J. Berakdar and Cappello, \{C. D.\}", year = "2001", month = aug, day = "14", doi = "10.1088/0953-4075/34/15/313", language = "English", volume = "34", pages = "3073--3087", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "15", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Conduction band electronic structure of metallic beryllium @article{361e1232b3174031a99356bcb9d4289f, title = "Conduction band electronic structure of metallic beryllium", abstract = "We have measured the bulk energy-momentum-resolved density of the conduction band of metallic beryllium by means of electron momentum spectroscopy. From the data we have determined the band dispersion, occupied bandwidth, electron momentum density and density of states. The experimental results are compared with theoretical band-structure calculations performed within the full-potential linear muffin-tin orbital (FP-LMTO) approximation. There is good agreement between experiment and theory for the shape and intensity of the conduction band provided multiple-scattering and hole lifetime effects are included. The measured occupied bandwidth is 11.15 ± 0.15 eV, which is larger than that predicted by our LMTO calculation, but agrees well with previous experimental and theoretical data. The experiment also reveals that the band dispersion is narrower in momentum compared to theory, the difference reaching as much as 0.15 au near the free-electron Fermi momentum.", author = "Sashin, \{V. A.\} and Bolorizadeh, \{M. A.\} and Kheifets, \{A. S.\} and Ford, \{M. J.\}", year = "2001", month = may, day = "14", doi = "10.1088/0953-8984/13/19/303", language = "English", volume = "13", pages = "4203--4219", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "19", } . Journal of Physics Condensed Matter.

On different mechanisms of the two-electron atomic photoionization @article{6b3fd3ac1a3e4a0ebcf1ebf921f888fa, title = "On different mechanisms of the two-electron atomic photoionization", abstract = "We evaluate the partial contribution of different mechanisms leading to the single-photon two-electron atomic ionization processes: photoionization with excitation and double photoionization. We estimate the photon energy at which the shake-off mechanism becomes dominant over the two-step mechanism. We support our findings by scaling the photoionization cross sections of neutral atomic species with the electron scattering cross sections on the corresponding positive ions.", author = "Anatoli Kheifets", year = "2001", month = apr, day = "28", doi = "10.1088/0953-4075/34/8/102", language = "English", volume = "34", pages = "L247--L252", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "8", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Double ionization of helium by electron-impact @article{8c8f12b31abd447b9ab67de0a4d5d9c0, title = "Double ionization of helium by electron-impact: Complete pictures of the four-body breakup dynamics", abstract = "A kinematically complete experiment for 2 keV electron impact on helium was carried out. For this purpose, a large part of the 12-dimensional, four-particle final-state momentum space was mapped with sufficient statistics to extract fully differential cross sections. The obtained data was compared with calculations performed within the same first Born model.", author = "A. Dorn and A. Kheifets and Schr{\"o}ter, \{C. D.\} and B. Najjari and C. H{\"o}hr and R. Moshammer and J. Ullrich", year = "2001", month = apr, day = "23", doi = "10.1103/PhysRevLett.86.3755", language = "English", volume = "86", pages = "3755--3758", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "17", } . Physical Review Letters.

Anisotropy of the electron momentum density of graphite studied by (γ, eγ) and (e, 2e) spectroscopy @article{cb49714071c043e0b3dceb6b47f5047a, title = "Anisotropy of the electron momentum density of graphite studied by (γ, eγ) and (e, 2e) spectroscopy", abstract = "The electron momentum density (EMD) of two different modifications of graphite has been measured and the results of the measurements have been compared with theoretical calculations from three different theories: a full potential linear muffin-tin orbital, a modified augmented plane wave, and a pseudopotential calculation. Experimental results have been obtained by two different methods. The complete three-dimensional EMD is determined by inelastic photon-electron scattering, i.e., by the so-called (γ, eγ) experiment, and by electron-electron scattering, the (e, 2e) experiment, cuts in the spectral electron momentum density are studied. For the (γ, eγ) experiment 180 keV synchrotron radiation from the PETRA storage ring at the Deutsches Elektronen-Synchrotron has been used with coincident detection of the recoil electrons. The (e, 2e) experiments were carried out at the new (e, 2e) spectrometer at the Australian National University using 40 keV primary electron energy and simultaneous detection of the outgoing electrons in an equal energy sharing mode. As samples we have prepared approximately 20 nm thin self-supporting graphite foils either by thermal evaporation (TE) or by laser plasma ablation (LPA). They are thin enough to suppress in essence electron multiple scattering. Electron diffraction analysis revealed that the LPA foil contains graphitic basal planes with a random distribution of c axes, whereas the TE foil was strongly c-axis oriented in the sense that the basal planes were parallel to the foil surface. In the analysis of the results special attention was devoted to anisotropies in the EMD revealed by comparison of TE and LPA foils. The (e, 2e) measurements showed furthermore a strong orientation dependence of the intensity of π and σ states (here we have for comparison additionally measured highly oriented pyrolytic graphite). The EMD{\textquoteright}s obtained by both techniques show anisotropies in the momentum distribution of graphite and are discussed in view of the theoretical results.", author = "T. Sattler and Th Tschentscher and Schneider, \{J. R.\} and M. Vos and Kheifets, \{A. S.\} and Lun, \{D. R.\} and E. Weigold and G. Dollinger and H. Bross and F. Bell", year = "2001", month = mar, day = "30", doi = "10.1103/PhysRevB.63.155204", language = "English", volume = "63", journal = "Physical Review B - Condensed Matter and Materials Physics", issn = "1098-0121", publisher = "American Physical Society", number = "15", } . Physical Review B - Condensed Matter and Materials Physics.

Momentum profiles of aluminum @article{4a1fd6320801444aa240b547dd6b7752, title = "Momentum profiles of aluminum", abstract = "Electron momentum spectroscopy is a tool ideally suited for the study of the energy-resolved momentum densities. Here we present new data from a high-energy EMS experiment using 50 keV incoming and 25 keV outgoing electrons. Momentum profiles have been measured from a thin aluminum film for the 2p core level and the valence band near Ef. The resolution of these momentum profiles, as well as the effects of multiple scattering are discussed. It is found that the high-energy EMS experiment measures momentum densities with superior resolution and very little background.", author = "M. Vos and Kheifets, \{A. S.\} and E. Weigold", year = "2001", month = mar, doi = "10.1016/S0368-2048(00)00284-X", language = "English", volume = "114-116", pages = "1031--1036", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", note = "8th International Conference on Electronic Spectroscopy and Structure (ICESS-8) ; Conference date: 08-08-2000 Through 12-08-2000", } . Journal of Electron Spectroscopy and Related Phenomena.

LAHMAM-BENNANI, A, DUGUET, A, GABORIAUD, MN, THOUIL, I, LECAS, M, KHEIFETS, A, BERAKDAR, J, DAL CAPPELLO, C(2001). Complete experiments for the double ionization of He: (e, 3e) cross sections at 1 keV impact energy and small momentum transfer . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 34. (15). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3073-3087.

VOS, M, KHEIFETS, AS, WEIGOLD, E, ARYASETIAWAN, F(2001). Electron correlation effects in the spectral momentum density of graphite . PHYSICAL REVIEW B. 63. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString art. no.-033108.

T. Sattler, Th. Tschentscher, J. R. Schneider, M. Vos, A. S. Kheifets, D. R. Lun, E. Weigold, G. Dollinger, H. Bross, F. Bell (2001). Anisotropy of the electron momentum density of graphite studied by <math display="inline"> <mo>(</mo> <mi>γ</mi> <mo>,</mo> <mi>e</mi> <mi>γ</mi> <mo>)</mo> </math> and <math display="inline"> <mn/> <mo>(</mo> <mi>e</mi> <mo>,</mo> <mn>2</mn> <mi>e</mi> <mo>)</mo> <mn/> </math> spectroscopy . Physical Review B.

A. S. Kheifets, M. Vos, E. Weigold(2001). The spectral momentum density of aluminium, copper and gold measured by electron momentum spectroscopy . Zeitschrift fur Physikalische Chemie. 215. (10). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1323--1339. Walter de Gruyter GmbH

C Dawson, S Cvejanovic, D P Seccombe, T J Reddish, F Maulbetsch, A Huetz, J Mazeau, A S Kheifets (2001). Helium (gamma, 2e) triple differential cross sections at an excess energy of 60 eV . Journal of Physics B: Atomic, Molecular and Optical Physics.

DORN, A, KHEIFETS, A, SCHROTER, CD, NAJJARI, B, HOHR, C, MOSHAMMER, R, ULLRICH, J(2001). Double ionization of helium by electron-impact: Complete pictures of the four-body breakup dynamics . PHYSICAL REVIEW LETTERS. 86. (17). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3755-3758.

DAWSON, C, CVEJANOVIC, S, SECCOMBE, DP, REDDISH, TJ, MAULBETSCH, F, HUETZ, A, MAZEAU, J, KHEIFETS, AS(2001). Helium (gamma, 2e) triple differential cross sections at an excess energy of 60 eV . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 34. (16). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L525-L533.

M. Vos, A. S. Kheifets, E. Weigold, F. Aryasetiawan (2001). Electron correlation effects in the spectral momentum density of graphite . Physical Review B.

Dorn, A, Kheifets, A, Schr&#246;ter, CD, Najjari, B, H&#246;hr, C, Moshammer, R, Ullrich, J (2001). Double ionization of helium by electron-impact: Complete pictures of the four-body breakup dynamics . Physical Review Letters.

SATTLER, T, TSCHENTSCHER, T, SCHNEIDER, JR, VOS, M, KHEIFETS, AS, LUN, DR, WEIGOLD, E, DOLLINGER, G, BROSS, H, BELL, F(2001). Anisotropy of the electron momentum density of graphite studied by (gamma,e gamma) and (e,2e) spectroscopy . PHYSICAL REVIEW B. 63. (15).

V A Sashin, M A Bolorizadeh, A S Kheifets, M J Ford (2001). Conduction band electronic structure of metallic beryllium . Journal of Physics: Condensed Matter.

KHEIFETS, AS, VOS, M, WEIGOLD, E(2001). The spectral momentum density of aluminium, copper and gold measured by electron momentum spectroscopy . ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS. 215. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1323-1339.

BOLOGNESI, P, CAMILLONI, R, CORENO, M, TURRI, G, BERAKDAR, J, KHEIFETS, AS, AVALDI, L(2001). Complementary TDCS for the photo-double ionization of He at 40 eV above the threshold in unequal energy-sharing conditions . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 34. (15). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3193-3203.

M. Vos, A. S. Kheifets, E. Weigold, F. Aryasetiawan(2001). Electron correlation effects in the spectral momentum density of graphite . Physical Review B-Condensed Matter. 63. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 331081--331084. American Institute of Physics

Lahmam-Bennani, A, Duguet, A, Gaboriaud, MN, Thouil, I, Lecas, M, Kheifets, A, Berakdar, J, Dal Cappello, C (2001). Complete experiments for the double ionization of He: (e, 3e) cross sections at 1 keV impact energy and small momentum transfer . Journal of Physics B: Atomic, Molecular and Optical Physics.

Anatoli Kheifets (2001). On different mechanisms of the two-electron atomic photoionization . Journal of Physics B: Atomic, Molecular and Optical Physics.

Anatoli Kheifets, T Sattler, T Tschentscher, J.R. Schneider, Maarten Vos, D R Alan Lun, Erich Weigold, G. Dollinger, H Bross, F Bell(2001). Anisotropy of the electron momentum density of graphite studied by (y,ey) and (e,2e) spectroscopy . Physical Review B. 63. (15). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 155204/1--17. American Physical Society

SASHIN, VA, BOLORIZADEH, MA, KHEIFETS, AS, FORD, MJ(2001). Conduction band electronic structure of metallic beryllium . JOURNAL OF PHYSICS-CONDENSED MATTER. 13. (19). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4203-4219.

KHEIFETS, A(2001). On different mechanisms of the two-electron atomic photoionization . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 34. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L247-L252.

Bolognesi, P, Camilloni, R, Coreno, M, Turri, G, Berakdar, J, Kheifets, AS, Avaldi, L (2001). Complementary TDCS for the photo-double ionization of He at 40 eV above the threshold in unequal energy-sharing conditions . Journal of Physics B: Atomic, Molecular and Optical Physics.

A. S. Kheifets, M. Vos, E. Weigold (2001). The spectral momentum density of aluminium, copper and gold measured by electron momentum spectroscopy . Zeitschrift für Physikalische Chemie.

Equal energy-sharing double photoionization of helium from near-threshold to high energies @article{74377b7d71b340c19c12cdf496e90914, title = "Equal energy-sharing double photoionization of helium from near-threshold to high energies", abstract = "The symmetric amplitude of the helium equal energy-sharing double photoionization (DPI) was calculated ab initio on a broad range of energies. Generation of equal energy-sharing triple differential cross sections (TDCS) for arbitrary geometry and polarization of the photons were allowed. This generation determines the Gaussian magnitude and width parameters.", author = "Kheifets, \{A. S.\} and Igor Bray", year = "2000", month = dec, doi = "10.1103/PhysRevA.62.065402", language = "English", volume = "62", pages = "65402--65401", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "6", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Electronic band structure of metallic calcium measured by electron momentum spectroscopy @article{d23db27e2c3942909d9a7c10ae73dc19, title = "Electronic band structure of metallic calcium measured by electron momentum spectroscopy", abstract = "We have measured the bulk energy-momentum resolved conduction band structure of metallic calcium using electron momentum spectroscopy (EMS). From the EMS data we have extracted the band dispersion, occupied bandwidth and density of states. The experimental results are compared with band structure calculations performed within the linear muffin-tin orbital (LMTO) approximation. The free-electron parabola expected for the dispersion relation in a metallic solid is clearly reproduced in the experimental data and is in good agreement with our calculation. A background produced by multiple-scattering events within the target is also evident in the EMS results. In order to make a quantitative comparison, we have included the effects of multiple scattering in the calculation using a Monte Carlo (MC) simulation. The results of this procedure reproduce the measured conduction band features and background intensity very well. The occupied bandwidth is measured to be 3.3±0.2 eV, and agrees with previous measurements and the value predicted by our LMTO calculation when the MC simulation is included. However, the experiment indicates that the band dispersion curve is narrower in momentum by as much as 0.1 au compared with the theory. We have also made measurements of the energies of the 3s and 3p core levels in metallic calcium, and obtained values of 45.0±0.4 eV and 25.6±0.2 eV respectively. These results are in good agreement with previous experiments.", author = "Sashin, \{V. A.\} and Bolorizadeh, \{M. A.\} and Kheifets, \{A. S.\} and Ford, \{M. J.\}", year = "2000", month = nov, day = "13", doi = "10.1088/0953-8984/12/45/304", language = "English", volume = "12", pages = "9407--9423", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "45", } . Journal of Physics Condensed Matter.

Double-photoionization calculations of the helium metastable 2 1,3S states @article{f4d915f2367843758d71050f30b0b23c, title = "Double-photoionization calculations of the helium metastable 2 1,3S states", abstract = "The excitations of the metastable states of helium were analyzed for the double photoionization and ionization effects. The electron transitions were described using momentum space formulations of the close-coupling theory. The range of photon energy from double-photoionization threshold level to the asymptotic level was covered by the investigation. The contributions of the different methods of two-electron photoionization in both the metastable and ground states were discussed.", author = "Kheifets, \{A. S.\} and A. Ipatov and M. Arifin and Igor Bray", year = "2000", month = nov, doi = "10.1103/PhysRevA.62.052724", language = "English", volume = "62", pages = "52724--52721", journal = "Physical Review A - Atomic, Molecular, and Optical Physics", issn = "1050-2947", publisher = "American Physical Society", number = "5", } . Physical Review A - Atomic, Molecular, and Optical Physics.

Fermi-surface and electron correlation in Al studied by Compton scattering @article{2d8c96c679c341bda52e8790631a20f9, title = "Fermi-surface and electron correlation in Al studied by Compton scattering", abstract = "We have studied the electron-momentum density distribution in Al using the coincidence as well as the conventional high-resolution Compton scattering technique. In order to interpret the results, corresponding band theory based computations of the electron momentum density (EMD) and the Compton profiles (CPs) have been carried out. Our focus here is on determining the size of the break ZF in the EMD at the Fermi momentum. For this purpose, differences between measurements and theoretical predictions are analyzed in terms of a simple model for describing electron correlation effects which are missing from the independent particle band theory framework; the model involves ZF as the only adjustable parameter. A good fit with the coincidence measurements is obtained for ZF of about 0.7, while the CP data yields ZF = 0.7 to 0.8. This study suggests that, in sharp contrast to the case of Li where recent high-resolution Compton work indicates ZF≈0, the standard picture of the interacting electron gas is substantially correct in Al.", author = "P. Suortti and T. Buslaps and V. Honkim{\"a}ki and C. Metz and A. Shukla and Th Tschentscher and J. Kwiatkowska and F. Maniawski and A. Bansil and S. Kaprzyk and Kheifets, \{A. S.\} and Lun, \{D. R.\} and T. Sattler and Schneider, \{J. R.\} and F. Bell", year = "2000", month = mar, doi = "10.1016/S0022-3697(99)00324-8", language = "English", volume = "61", pages = "397--401", journal = "Journal of Physics and Chemistry of Solids", issn = "0022-3697", publisher = "Elsevier Ltd.", number = "3", note = "International Workshop on Inelastic X-ray Scattering ; Conference date: 18-10-1998 Through 21-10-1998", } . Journal of Physics and Chemistry of Solids.

Protodouble ionization of helium at an excess energy of 40 eV @article{7c85412ce81c4c7b9d529286a8f641f0, title = "Protodouble ionization of helium at an excess energy of 40 eV", abstract = "Angular correlation in the two-electron continuum of the He double photoionization has been studied, both experimentally and theoretically, for equal and unequal energy sharing conditions at the photon energy of 40 eV above the threshold. The triple differential cross sections have been measured in the plane perpendicular to the photon direction using the multi-coincidence detection technique of Reddish et al at the Daresbury Synchrotron Radiation Source. Recent modifications to the bending-magnet beam line allowed an effective cancellation of the circular polarization at the target, leaving a relatively high degree of linear polarization (Stokes parameters: S3 = S2 ≅ 0, S1 = 0.8). The measured cross sections are compared with the calculations using the 3C method of Maulbetsch and Briggs and the convergent close coupling method of Kheifets and Bray. Good agreement between theory and experiment has been found in most cases, except for the unequal energy sharing when one of the escaping electrons is detected in a direction close to the polarization axis.", author = "S. Cvejanovi{\'c} and Wightman, \{J. P.\} and Reddish, \{T. J.\} and F. Maulbetsch and Macdonald, \{M. A.\} and Kheifets, \{A. S.\} and I. Bray", year = "2000", month = jan, day = "28", doi = "10.1088/0953-4075/33/2/311", language = "English", volume = "33", pages = "265--283", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "2", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Energy-resolved momentum densities for the valence band of a nanoscale Si single crystal @article{ac92f8f497f643dcad383c5d936e5ff0, title = "Energy-resolved momentum densities for the valence band of a nanoscale Si single crystal", abstract = "We have measured the energy-and momentum-resolved band structure, and ground state of occupation of the bands, for a crystalline silicon sample along the (100) and (110) directions. Band structures were determined directly by the technique of electron momentum spectroscopy (EMS) for a self-supporting Si membrane with a thickness of approximately 7 nm. We compare our experimental results with ab initio calculations for bulk crystalline silicon performed within the linear muffin tin orbital approximation. Qualitative agreement is seen between experiment and theory for the main valence band peak. Additional intensity is observed in the measurement on either side of the main peak and is attributed mainly to multiple-scattering events. Satellite structure could also be present in these additional features, although there is no direct evidence for this.", author = "Sashin, \{V. A.\} and Canney, \{S. A.\} and Ford, \{M. J.\} and Bolorizadeh, \{M. A.\} and Oliver, \{D. R.\} and Kheifets, \{A. S.\}", year = "2000", month = jan, day = "17", doi = "10.1088/0953-8984/12/2/303", language = "English", volume = "12", pages = "125--136", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "2", } . Journal of Physics Condensed Matter.

CVEJANOVIC, S, WIGHTMAN, JP, REDDISH, TJ, MAULBETSCH, F, MACDONALD, MA, KHEIFETS, AS, BRAY, I(2000). Photodouble ionization of helium at an excess energy of 40 eV . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 33. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 265-283.

KHEIFETS, AS, BRAY, I(2000). Equal energy-sharing double photoionization of helium from near-threshold to high energies . PHYSICAL REVIEW A. 62. (6).

KHEIFETS, AS, IPATOV, A, ARIFIN, M, BRAY, I(2000). Double-photoionization calculations of the helium metastable 2 S-1,S-3 states . PHYSICAL REVIEW A. 62. (5). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString art. no.-052724.

SASHIN, VA, BOLORIZADEH, MA, KHEIFETS, AS, FORD, MJ(2000). Electronic band structure of metallic calcium measured by electron momentum spectroscopy . JOURNAL OF PHYSICS-CONDENSED MATTER. 12. (45). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 9407-9423.

S Cvejanovic, J P Wightman, T J Reddish, F Maulbetsch, M A MacDonald, A S Kheifets, I Bray (2000). Photodouble ionization of helium at an excess energy of 40 eV . Journal of Physics B: Atomic, Molecular and Optical Physics.

Anatoli Kheifets, A Ipatov, M Arifin, Igor Bray(2000). Double-photoionization caclculations of the helium mestastable 21,3 S states . Physical Review A: Atomic, Molecular and Optical Physics. 62. (ISI). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 052724. American Physical Society

V A Sashin, S A Canney, M J Ford, M A Bolorizadeh, D R Oliver, A S Kheifets (2000). Energy-resolved momentum densities for the valence band of a nanoscale Si single crystal . Journal of Physics: Condensed Matter.

SASHIN, VA, CANNEY, SA, FORD, MJ, BOLORIZADEH, MA, OLIVER, DR, KHEIFETS, AS(2000). Energy-resolved momentum densities for the valence band of a nanoscale Si single crystal . JOURNAL OF PHYSICS-CONDENSED MATTER. 12. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 125-136.

A. S. Kheifets, Igor Bray (2000). Equal energy-sharing double photoionization of helium from near-threshold to high energies . Physical Review A.

A. S. Kheifets, A. Ipatov, M. Arifin, Igor Bray (2000). Double-photoionization calculations of the helium metastable <math display="inline"> <mn>2</mn> <mrow> <msup> <mrow> <mi/> </mrow> <mrow> <mn>1</mn> <mo>,</mo> <mn>3</mn> </mrow> </msup> </mrow> <mi>S</mi> </math> states . Physical Review A.

V A Sashin, M A Bolorizadeh, A S Kheifets, M J Ford (2000). Electronic band structure of metallic calcium measured by electron momentum spectroscopy . Journal of Physics: Condensed Matter.

Anatoli Kheifets, R Cvejanovic, J Wightman, T Reddish, F Maulbetsch, Marian McDonald, Igor Bray(2000). Photodouble Ionization of Helium at an Excess Energy of 40 eV . Journal of Physics B: Atomic, Molecular and Optical Physics. 33. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 265--283. Institute of Physics Publishing

Comparative experimental and theoretical investigation of the electron-impact double ionization of He in the keV regime @article{39d8aa7002b64d739a66592021e4ff13, title = "Comparative experimental and theoretical investigation of the electron-impact double ionization of He in the keV regime", abstract = "We determine, both experimentally and theoretically, the fully resolved fivefold differential cross section (5DCS) of double ionization of helium by 5.6 keV electron impact. Symmetric energy sharing between the two ejected electrons is investigated at the excess energy of 8 and 20 eV with 0.22 and 0.24 au momentum transfer, respectively. Absolute 5DCS are determined by normalizing the experimental data to the well established single-ionization cross sections. The calculation is performed by using the convergent close-coupling method for the interaction between the two slow ejected electrons, together with the first Born approximation for the interaction of the fast incident electron with the atom. Experimental and theoretical 5DCS tend to agree in shape but disagree in magnitude by factors of three and 14 for the 20 and 8 eV excess energies, respectively. The small momentum transfer invites absolute comparison of the present electron-impact double-ionization results with the corresponding double-photoionization experiment and theory. Theoretically, the momentum transfer is sufficiently close to zero to show the scaling between the two scattering processes. This smallness of the momentum transfer also makes the calculated 5DCS nearly invariant with respect to simultaneous inversion of the momenta of the two ejected electrons.", author = "Anatoli Kheifets and Igor Bray and A. Lahmam-Bennani and A. Duguet and I. Taouil", year = "1999", month = nov, day = "14", doi = "10.1088/0953-4075/32/21/301", language = "English", volume = "32", pages = "5047--5065", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "21", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Electronic band structure of magnesium and magnesium oxide @article{6e24bb0d80e347e99257e4a80500310b, title = "Electronic band structure of magnesium and magnesium oxide: Experiment and theory", abstract = "Electron momentum spectroscopy (EMS) has been used to measure the valence band electronic structure of thin magnesium and magnesium oxide films. The band structures have also been calculated within the linear muffin-tin orbital (LMTO) approximation. The free-electron-like parabola characteristic of metallic solids was observed for magnesium with a bandwidth of approximately 6eV, in agreement with previous measurements. The inclusion of energy broadening due to finite hole-lifetime effects and a Monte Carlo simulation of multiple scattering events gives good agreement between calculated and measured band structures. However, we measure a much higher intensity due to plasmon excitation compared with the simulated intensity. Upon oxidation the valence structure splits into two distinct, less dispersive bands typical of an ionic solid. Intensity due to plasmon excitation was almost completely absent in the experimental spectra for magnesium oxide. The LMTO calculation reproduces the overall structure and dispersion range of the oxide. The measured and calculated energy gap between upper and lower valence bands and their relative intensities do not agree quantitatively. This discrepancy may be due to a contribution of magnesium s states to the predominantly oxygen p states in the upper band.", author = "Canney, \{S. A.\} and Sashin, \{A. V.\} and Ford, \{M. J.\} and Kheifets, \{A. S.\}", year = "1999", month = oct, day = "4", doi = "10.1088/0953-8984/11/39/308", language = "English", volume = "11", pages = "7507--7522", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "39", } . Journal of Physics Condensed Matter.

Experimental and theoretical study of linear and circular dichroism in helium double photoionization @article{7588bc1cd1374365b160f051c812f6e7, title = "Experimental and theoretical study of linear and circular dichroism in helium double photoionization", abstract = "The fully resolved triply differential cross section (TDCS) of helium double photoionization with elliptically polarized light has been determined, both experimentally and theoretically, at the photon energy of 88 eV. The excess energy was shared between the photoelectron pair as 1 + 8, 3 + 6 and 4.5 + 4.5 eV. Simultaneous sign reversal of the Stokes parameters S1, S3 resulted in a profound change of shape of the TDCS. This effect can be attributed to the linear dichroism in the case of equal energy sharing, and a combination of the circular and linear dichroisms in the case of unequal energy sharing. Theoretical TDCS was obtained by employing the convergent close-coupling (CCC) method. In contrast to the previous work of Mergel et al (1998 Phys. Rev. Lett. 80 5301) who investigated the circular dichroism at 99 eV photon energy, good agreement is found between experimental and calculated TDCS in all cases.", author = "Anatoli Kheifets and Igor Bray and K. Soejima and A. Danjo and K. Okuno and A. Yagishita", year = "1999", month = sep, day = "14", doi = "10.1088/0953-4075/32/17/104", language = "English", volume = "32", pages = "L501--L509", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "17", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Full-potential linear-muffin-tin-orbital calculation of electron momentum densities of solids @article{945c0e0ef61342808a8af5a5e6a75674, title = "Full-potential linear-muffin-tin-orbital calculation of electron momentum densities of solids", abstract = "We calculate electron momentum densities of various crystalline solids by employing the linear-muffin-tin-orbital (LMTO) method. We use three levels of approximation to the LMTO: the simplest atomic sphere approximation (ASA), the ASA with overlap correction, and the full-potential (FP) LMTO. Although the band energies calculated using the ASA and the FP-LMTO are practically the same, there is a noticeable difference in the electron momentum densities which is not cured by making a simple overlap correction to the ASA-LMTO method.", author = "Kheifets, \{A. S.\} and Lun, \{D. R.\} and Savrasov, \{S. Yu\}", year = "1999", month = sep, day = "6", doi = "10.1088/0953-8984/11/35/314", language = "English", volume = "11", pages = "6779--6792", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "35", } . Journal of Physics Condensed Matter.

Convergent calculations for simultaneous electron-impact ionization-excitation of helium @article{c589b6524fcc4161a710d47a40a7ecc5, title = "Convergent calculations for simultaneous electron-impact ionization-excitation of helium", abstract = "Theoretical results are presented for electron-impact ionization of He(1s2), leaving the ion in the n = 2 excited states. The projectile-target interaction is described in the first-order plane-wave Born approximation, whereas the interaction between the ejected electron and the residual ion is treated non-perturbatively within the convergent close-coupling formalism. Comparison of the predictions from two entirely independent approaches, formulated either in coordinate or in momentum space, provides a basis for further systematic improvement of the models.", author = "Kheifets, \{A. S.\} and I. Bray and K. Bartschat", year = "1999", month = aug, day = "14", doi = "10.1088/0953-4075/32/15/104", language = "English", volume = "32", pages = "L433--L438", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "15", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Three-dimensional electron momentum densities of graphite and fullerene @article{a392cf281dd9449c94b1af547cba297d, title = "Three-dimensional electron momentum densities of graphite and fullerene: A comparison", abstract = "We report on the three-dimensional electron momentum densities (EMD) of graphite and fullerene obtained by a so-called (γ, eγ) experiment, i.e. the coincident detection of an inelastically scattered hard x-ray photon with its recoil electron. A monochromatized flux of 1012 photons s-1 at 150 keV from the high-energy x-ray wiggler beamline of the ESRF was directed onto thin graphite or fullerene targets. Comparison with a pseudopotential and a full-potential linear muffin-tin orbital calculation in the case of graphite is made. Inclusion of electron correlation via the Lam-Platzman correction is discussed. The experimental EMD of C60 shows stronger electron delocalization in the 'buckyball' compared to graphite, which is supported by theory.", author = "C. Metz and Th Tschentscher and P. Suortti and Kheifets, \{A. S.\} and Lun, \{D. R.\} and T. Sattler and Schneider, \{J. R.\} and F. Bell", year = "1999", month = may, day = "17", doi = "10.1088/0953-8984/11/19/312", language = "English", volume = "11", pages = "3933--3942", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "19", } . Journal of Physics Condensed Matter.

Determination of the energy-momentum densities of aluminium by electron momentum spectroscopy @article{a707487370174b6fa6f1ea8a91f0ae3f, title = "Determination of the energy-momentum densities of aluminium by electron momentum spectroscopy", abstract = "The energy-resolved momentum densities of thin polycrystalline aluminium films have been measured using electron momentum spectroscopy (EMS), for both the valence band and the outer core levels. The spectrometer used for these measurements has energy and momentum resolutions of around 1.0 eV and 0.15 atomic units, respectively. These measurements should, in principle, describe the electronic structure of the film very quantitatively, i.e. the dispersion and the intensity can be compared directly with theoretical spectral momentum densities for both the valence band and the outer core levels. Multiple scattering is found to hamper the interpretation somewhat. The core-level intensity distribution was studied with the main purpose of setting upper bounds on these multiple-scattering effects. Using this information we wish to obtain a full understanding of the valence band spectra using different theoretical models of the spectral function. These theoretical models differ significantly and only the cumulant expansion calculation that takes the crystal lattice into account seems to describe the data reasonably well.", author = "M. Vos and Kheifets, \{A. S.\} and E. Weigold and Canney, \{S. A.\} and B. Holm and F. Aryasetiawan and K. Karlsson", year = "1999", month = may, day = "10", doi = "10.1088/0953-8984/11/18/302", language = "English", volume = "11", pages = "3645--3661", journal = "Journal of Physics Condensed Matter", issn = "0953-8984", publisher = "IOP Publishing Ltd.", number = "18", } . Journal of Physics Condensed Matter.

C. Metz, Th. Tschentscher, P. Suortti, A. S. Kheifets, D. R. Lun, T. Sattler, J. R. Schneider, F. Bell (1999). Three-dimensional electron momentum density of aluminum by (gamma,e gamma) spectroscopy . Physical Review B.

C Metz, Th Tschentscher, P Suortti, A S Kheifets, D R Lun, T Sattler, J R Schneider, F Bell (1999). Three-dimensional electron momentum densities of graphite and fullerene: a comparison . Journal of Physics: Condensed Matter.

A. Kheifets, I. Bray(1999). Photoionization with excitation and double photoionization of two-electron atomic targets . Journal De Physique. IV : JP. 9. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString Pr6--79 -- Pr6--83. EDP Sciences

KHEIFETS, A, BRAY, I, LAHMAM-BENNANI, A, DUGUET, A, TAOUIL, I(1999). A comparative experimental and theoretical investigation of the electron-impact double ionization of He in the keV regime . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 32. (21). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 5047-5065.

CANNEY, SA, SASHIN, VA, FORD, MJ, KHEIFETS, AS(1999). Electronic band structure of magnesium and magnesium oxide: experiment and theory . JOURNAL OF PHYSICS-CONDENSED MATTER. 11. (39). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 7507-7522.

Anatoli Kheifets, Igor Bray, A Lahmam-Bennani, A Duguet, I Taouil (1999). A comparative experimental and theoretical investigation of the electron-impact double ionization of He in the keV regime . Journal of Physics B: Atomic, Molecular and Optical Physics.

METZ, C, TSCHENTSCHER, T, SUORTTI, P, KHEIFETS, AS, LUN, DR, SATTLER, T, SCHNEIDER, JR, BELL, F(1999). Three-dimensional electron momentum density of aluminum by (gamma,e gamma) spectroscopy . PHYSICAL REVIEW B. 59. (16). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 10512-10520.

S A Canney, V A Sashin, M J Ford, A S Kheifets (1999). Electronic band structure of magnesium and magnesium oxide: experiment and theory . Journal of Physics: Condensed Matter.

VOS, M, KHEIFETS, AS, WEIGOLD, E, CANNEY, SA, HOLM, B, ARYASETIAWAN, F, KARLSSON, K(1999). Determination of the energy-momentum densities of aluminium by electron momentum spectroscopy . JOURNAL OF PHYSICS-CONDENSED MATTER. 11. (18). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3645-3661.

M Vos, A S Kheifets, E Weigold, S A Canney, B Holm, F Aryasetiawan, K Karlsson (1999). Determination of the energy-momentum densities of aluminium by electron momentum spectroscopy . Journal of Physics: Condensed Matter.

Anatoli Kheifets, Igor Bray, K Soejima, A Danjo, K Okuno, A Yagishita (1999). Experimental and theoretical study of linear and circular dichroism in helium double photoionization . Journal of Physics B: Atomic, Molecular and Optical Physics.

A S Kheifets, I Bray, K Bartschat (1999). Convergent calculations for simultaneous electron-impact ionization-excitation of helium . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS, LUN, DR, SAVRASOV, SY(1999). Full-potential linear-muffin-tin-orbital calculation of electron momentum densities of solids . JOURNAL OF PHYSICS-CONDENSED MATTER. 11. (35). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 6779-6792.

KHEIFETS, AS, BRAY, I, BARTSCHAT, K(1999). Convergent calculations for simultaneous electron-impact ionization-excitation of helium . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 32. (15). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L433-L438.

A S Kheifets, D R Lun, S Yu Savrasov (1999). Full-potential linear-muffin-tin-orbital calculation of electron momentum densities of solids . Journal of Physics: Condensed Matter.

KHEIFETS, A, BRAY, I, SOEJIMA, K, DANJO, A, OKUNO, K, YAGISHITA, A(1999). Experimental and theoretical study of linear and circular dichroism in helium double photoionization . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 32. (17). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L501-L509.

M. Vos, S. A. Canney, A. S. Kheifets, D. R. Lun, E. Weigold(1999). Determination of the anisotropic electronic structure of graphite by (e,2e) spectroscopy . Journal De Physique. IV : JP. 9. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString Pr6--153 -- Pr6--156. EDP Sciences

METZ, C, TSCHENTSCHER, T, SUORTTI, P, KHEIFETS, AS, LUN, DR, SATTLER, T, SCHNEIDER, JR, BELL, F(1999). Three-dimensional electron momentum densities of graphite and fullerene: a comparison . JOURNAL OF PHYSICS-CONDENSED MATTER. 11. (19). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3933-3942.

Absolute triple differential cross sections for photo-double ionization of helium - Experiment and theory @article{31d0d7634b644abd987208846fe80d84, title = "Absolute triple differential cross sections for photo-double ionization of helium - Experiment and theory", abstract = "We have measured absolute triple differential cross sections for photo-double ionization of helium at 20 eV excess. The measurement covers the full ranges of energy sharing and emission angles of the two photoelectrons. We compare our data for selected geometries with the convergent close-coupling (CCC) calculations as well as 2SC calculations by Pont and Shakeshaft and 3C calculations by Maulbetsch and Briggs. In terms of the absolute magnitude and the trend in the shapes of the triple differential cross section for different geometries we find good agreement of the CCC and published 2SC calculations with our measurement, though differences with respect to the observed shape of individual patterns still exist.", author = "H. Br{\"a}uning and R. D{\"o}rner and Cocke, \{C. L.\} and Prior, \{M. H.\} and B. Kr{\"a}ssig and Kheifets, \{A. S.\} and I. Bray and A. Br{\"a}uning-Demian and K. Carnes and S. Dreuil and V. Mergel and P. Richard and J. Ullrich and H. Schmidt-B{\"o}cking", year = "1998", month = dec, day = "14", doi = "10.1088/0953-4075/31/23/012", language = "English", volume = "31", pages = "5149--5160", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "23", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Application of the CCC method to the calculation of helium double-photoionization triply differential cross sections @article{02b3e084d5af4320a8986a8e5af3f9d4, title = "Application of the CCC method to the calculation of helium double-photoionization triply differential cross sections", abstract = "The convergent close-coupling (CCC) formalism is employed to calculate the fully resolved triply differential cross section (TDCS) for helium double photoionization. This is the first ab initio calculation of the kind where all three gauges of the electromagnetic interaction produce TDCS within a few per cent of each other. Comparison is made with the experimental data in the range of photon energies 10-53 eV above the threshold, both for equal and unequal energy sharing. The present calculations agree very well, both in shape and where available in magnitude, with the experimental data obtained at the BESSY storage ring (Berlin, Germany) (Schmidt et al 1996 J. Electron Spectrosc. Relat. Phenom. 79 279 and references therein). In addition, excellent agreement is found with the calculations of Pont and Shakeshaft (1995 Phys. Rev. A 51 R2676).", author = "Kheifets, \{Anatoli S.\} and Igor Bray", year = "1998", month = may, day = "28", doi = "10.1088/0953-4075/31/10/002", language = "English", volume = "31", pages = "L447--L453", journal = "Journal of Physics B: Atomic, Molecular and Optical Physics", issn = "0953-4075", publisher = "Institute of Physics", number = "10", } . Journal of Physics B: Atomic, Molecular and Optical Physics.

Quantitative electron momentum spectroscopy of aluminum films @article{e8c32277c420445584ddf1cb1e24ab09, title = "Quantitative electron momentum spectroscopy of aluminum films", abstract = "We present measurements of the spectral momentum density of aluminum films and compare these results with two different theories. One theory is a standard band structure calculation, taking into account the lattice potential; the other theory neglects the lattice potential, but takes electron-electron correlations approximately into account. Near the Fermi level, the band structure calculations and jellium-type many-body calculations provide satisfactory results, especially if multiple scattering effects are taken into account. The measured intensity at binding energies exceeding the single-particle band width is too large, even after correction for multiple scattering effects for the band structure calculations. The jellium-type many-body calculations have more intensity than the band structure-type calculations at higher binding energies. However the sharp satellite features present in this theory are not observed in the experiment.", keywords = "Aluminum, Electron momentum spectroscopy, Many-body effects", author = "S. Canney and A. Kheifets and M. Vos and E. Weigold", year = "1998", month = mar, doi = "10.1016/s0368-2048(97)00135-7", language = "English", volume = "88-91", pages = "247--253", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", } . Journal of Electron Spectroscopy and Related Phenomena.

The electronic structure of different forms of solid carbon studied by electron momentum spectroscopy @article{dc877ade82114047afbfaa361b48d698, title = "The electronic structure of different forms of solid carbon studied by electron momentum spectroscopy", abstract = "The purpose of this paper is to first give an overview of the information obtained by electron momentum spectroscopy (EMS) on the electronic structure of different forms of solid carbon (single crystal graphite, polycrystalline carbon, different forms of amorphous carbon, and fullerenes). We show for sp2 bonded carbon that, with decreasing order, the structures observed change but certain basic features remain. sp3-bonded carbon films and fullerene films both have electronic structures different from these graphitic films. The results of EMS are compared with the results of other spectroscopic and scattering techniques. It is argued that the combination of energy and momentum resolution is crucial in order to get a clear picture of the changes in the electronic structure due to the changes in atomic arangements. Only EMS resolves both energy and momentum for all these solids.", keywords = "Carbon, Electron momentum spectroscopy, Energy resolved momentum densities", author = "M. Vos and A. Kheifets and E. Weigold and Canney, \{S. A.\} and Kurp, \{F. F.\}", year = "1998", month = feb, doi = "10.1016/s0368-2048(97)00101-1", language = "English", volume = "87", pages = "231--251", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", number = "3", } . Journal of Electron Spectroscopy and Related Phenomena.

VOS, M, KHEIFETS, A, WEIGOLD, E, CANNEY, SA, KURP, FF(1998). The electronic structure of different forms of solid carbon studied by electron momentum spectroscopy . JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. 87. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 231-251.

BRAUNING, H, DORNER, R, COCKE, CL, KRASSIG, B, KHEIFETS, AS, BRAY, I, BRAUNING-DEMAIN, A, CARNES, K, DREUIL, S, MERGEL, V, et al.(1998). Absolute triple differential cross sections for photo-double ionization of helium - experiment and theory . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 31. (23). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 5149-5160.

GUO, X, FANG, Z, KHEIFETS, AS, CANNEY, SA, VOS, M, MCCARTHY, IE, WEIGOLD, E(1998). Spectral momentum density of electrons in copper . PHYSICAL REVIEW B. 57. (11). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 6333-6341.

Br&#228;uning, H, D&#246;rner, R, Cocke, CL, Kr&#228;ssig, B, Kheifets, AS, Bray, I, Br&#228;uning-Demain, A, Carnes, K, Dreuil, S, Mergel, V, et al. (1998). Absolute triple differential cross sections for photo-double ionization of helium -: experiment and theory . Journal of Physics B: Atomic, Molecular and Optical Physics.

X. Guo, Z. Fang, A. S. Kheifets, S. A. Canney, M. Vos, I. E. McCarthy, E. Weigold (1998). Spectral momentum density of electrons in copper . Physical Review B.

M. Vos, A. Kheifets, E. Weigold, S.A. Canney, F.F. Kurp (1998). The electronic structure of different forms of solid carbon studied by electron momentum spectroscopy . Journal of Electron Spectroscopy and Related Phenomena.

S. Rioual, S. Iacobucci, D. Neri, A. S. Kheifets, G. Stefani (1998). Momentum distribution and valence-band reconstruction in graphite by grazing incidence <math display="inline"> <mn/> <mo>(</mo> <mi>e</mi> <mo>,</mo> <mn>2</mn> <mi>e</mi> <mo>)</mo> <mn/> </math> spectroscopy . Physical Review B.

RIOUAL, S, IACOBUCCI, S, NERI, D, KHEIFETS, AS, STEFANI, G(1998). Momentum distribution and valence-band reconstruction in graphite by grazing incidence (e,2e) spectroscopy . PHYSICAL REVIEW B. 57. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2545-2549.

Z. Fang, X. Guo, S. A. Canney, S. Utteridge, M. J. Ford, I. E. McCarthy, A. S. Kheifets, M. Vos, E. Weigold (1998). Valence-band energy-momentum densities of amorphous <math display="inline"> <mrow> <msub> <mrow> <mi mathvariant="normal">SiO</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msub> </mrow> </math> by <math display="inline"> <mn/> <mo>(</mo> <mi>e</mi> <mo>,</mo> <mn>2</mn> <mi>e</mi> <mo>)</mo> <mn/> </math> spectroscopy . Physical Review B.

Anatoli S. Kheifets, Igor Bray (1998). Effect of the ground-state correlations on the helium double photoionization and ionization with excitation . Physical Review A.

FANG, Z, GUO, X, CANNEY, SA, UTTERIDGE, S, FORD, MJ, MCCARTHY, IE, KHEIFETS, AS, VOS, M, WEIGOLD, E(1998). Valence-band energy-momentum densities of amorphous SiO2 by (e,2e) spectroscopy . PHYSICAL REVIEW B. 57. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4349-4357.

Anatoli S Kheifets, Igor Bray (1998). Application of the CCC method to the calculation of helium double-photoionization triply differential cross sections . Journal of Physics B: Atomic, Molecular and Optical Physics.

Anatoli S. Kheifets, Igor Bray(1998). Photoionization with excitation and double photoionization of the helium isoelectronic sequence . Physical Review A - Atomic, Molecular, and Optical Physics. 58. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4501--4511. American Physical Society

KHEIFETS, AS, BRAY, I(1998). Calculation of circular dichroism in helium double photoionization . PHYSICAL REVIEW LETTERS. 81. (21). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4588-4591.

Anatoli S. Kheifets, Igor Bray(1998). Calculation of circular dichroism in helium double photoionization . Physical Review Letters. 81. (21). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4588--4591. American Physical Society

KHEIFETS, AS, IACOBUCCI, S, RUOCCO, A, CAMILLONI, R, STEFANI, G(1998). Mechanism of the low-ejection-energy (e,2e) reaction on a graphite surface . PHYSICAL REVIEW B. 57. (12). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 7360-7368.

KHEIFETS, AS, BRAY, I(1998). Effect of the ground-state correlations on the helium double photoionization and ionization with excitation . PHYSICAL REVIEW A. 57. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2590-2595.

Anatoli S. Kheifets, Igor Bray (1998). Photoionization with excitation and double photoionization of the helium isoelectronic sequence . Physical Review A.

KHEIFETS, AS, BRAY, I(1998). Photoionization with excitation and double photoionization of the helium isoelectronic sequence . PHYSICAL REVIEW A. 58. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4501-4511.

KHEIFETS, AS, BRAY, I(1998). Application of the CCC method to the calculation of helium double-photoionization triply differential cross sections . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 31. (10). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L447-L453.

Anatoli S. Kheifets, Igor Bray (1998). Calculation of Circular Dichroism in Helium Double Photoionization . Physical Review Letters.

A. S. Kheifets, S. Iacobucci, A. Ruocco, R. Camilloni, G. Stefani (1998). Mechanism of the low-ejection-energy <math display="inline"> <mn/> <mo>(</mo> <mi>e</mi> <mo>,</mo> <mn>2</mn> <mi>e</mi> <mo>)</mo> <mn/> </math> reaction on a graphite surface . Physical Review B.

Z. Fang, X. Guo, S. Canney, S. Utteridge, M. Ford, I. McCarthy, A. Kheifets, M. Vos, E. Weigold(1998). Valence-band energy-momentum densities of amorphous by spectroscopy . Physical Review B - Condensed Matter and Materials Physics. 57. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4349--4357. American Physical Society

KHEIFETS, AS, VOS, M, WEIGOLD, E, BRUNGER, M, MCCARTHY, IE(1998). Absence of interchannel coupling in electron momentum spectroscopy . PHYSICAL REVIEW A. 58. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2815-2818.

A. S. Kheifets, M. Vos, E. Weigold, M. Brunger, I. E. McCarthy (1998). Absence of interchannel coupling in electron momentum spectroscopy . Physical Review A.

F. F. Kurp, M. Vos, Th. Tschentscher, A. S. Kheifets, J. R. Schneider, E. Weigold, F. Bell (1997). Three-dimensional electron momentum densities:A comparison of (γ,eγ) and (e,2e) spectroscopies . Physical Review B.

SAMARDZIC, O, CAMPBELL, L, BRUNGER, MJ, KHEIFETS, AS, WEIGOLD, E(1997). Autoionization in electron-helium collisions: an (e, 2e) investigation . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 30. (19). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4383-4394.

M. Vos, Z. Fang, S. Canney, A. Kheifets, I. E. McCarthy, E. Weigold (1997). Energy-momentum density of graphite by <math display="inline"> <mn/> <mo>(</mo> <mi>e</mi> <mo>,</mo> <mn>2</mn> <mi>e</mi> <mo>)</mo> <mn/> </math> spectroscopy . Physical Review B.

S.A Canney, M Vos, A.S Kheifets, X Guo, I.E McCarthy, E Weigold (1997). Electron momentum spectroscopy studies on the oxidation of aluminium . Surface Science.

Samardzic, O, Campbell, L, Brunger, MJ, Kheifets, AS, Weigold, E (1997). Autoionization in electron-helium collisions: an (e, 2e) investigation . Journal of Physics B: Atomic, Molecular and Optical Physics.

Brunger, MJ, Samardzic, O, Kheifets, AS, Weigold, E (1997). A study of autoionization phenomena in helium using (e, 2e) spectroscopy . Journal of Physics B: Atomic, Molecular and Optical Physics.

KURP, FF, VOS, M, TSCHENTSCHER, T, KHEIFETS, AS, SCHNEIDER, JR, WEIGOLD, E, BELL, F(1997). Three-dimensional electron momentum densities: A comparison of (gamma,e gamma) and (e,2e) spectroscopies . PHYSICAL REVIEW B. 55. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 5440-5447.

BRUNGER, MJ, SAMARDZIC, O, KHEIFETS, AS, WEIGOLD, E(1997). A study of autoionization phenomena in helium using (e, 2e) spectroscopy . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 30. (14). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3267-3285.

CANNEY, SA, VOS, M, KHEIFETS, AS, GUO, X, MCCARTHY, IE, WEIGOLD, E(1997). Electron momentum spectroscopy studies on the oxidation of aluminum . SURFACE SCIENCE. 382. (1-3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 241-257.

VOS, M, FANG, Z, CANNEY, S, KHEIFETS, A, MCCARTHY, IE, WEIGOLD, E(1997). Energy-momentum density of graphite by (e,2e) spectroscopy . Physical Review B. 56. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 963-966.

CANNEY, SA, VOS, M, KHEIFETS, AS, CLISBY, N, MCCARTHY, IE, WEIGOLD, E(1997). Measured energy-momentum densities of the valence band of aluminium . JOURNAL OF PHYSICS-CONDENSED MATTER. 9. (9). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1931-1950.

S A Canney, M Vos, A S Kheifets, N Clisby, I E McCarthy, E Weigold (1997). Measured energy - momentum densities of the valence band of aluminium . Journal of Physics: Condensed Matter.

X. Guo, S. Canney, A. S. Kheifets, M. Vos, Z. Fang, S. Utteridge, I. E. McCarthy, E. Weigold (1996). Electronic-structure investigation of oxidized aluminum films with electron-momentum spectroscopy . Physical Review B.

Anatoli S. Kheifets, Igor Bray (1996). Calculation of double photoionization of helium using the convergent close-coupling method . Physical Review A.

Bela Shanina, A.I. Veinger, A.S. Kheifets (1996). Magnetic field dependent microwave absorption in pure superconducting tin near T-c . Physica C: Superconductivity and its Applications.

GUO, X, CANNEY, S, KHEIFETS, AS, VOS, M, FANG, Z, UTTERIDGE, S, MCCARTHY, IE, WEIGOLD, E(1996). Electronic-structure investigation of oxidized aluminum films with electron-momentum spectroscopy . Physical Review B. 54. (24). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 17943-17953.

VEINGER, AI, KHEIFETS, AS(1996). Magnetic field dependent microwave absorption in pure superconducting tin near T-c . PHYSICA C. 269. (1-2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 29-34.

KHEIFETS, AS, BRAY, I(1996). Calculation of double photoionization of helium using the convergent close-coupling method . PHYSICAL REVIEW A. 54. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString R995-R997.

A S Kheifets, Y Q Cai (1995). Energy-resolved electron momentum densities of diamond-structure semiconductors . Journal of Physics: Condensed Matter.

SAMARDZIC, O, KHEIFETS, AS, WEIGOLD, E, SHANG, B, BRUNGER, MJ(1995). AN (E, 2E) STUDY OF HELIUM AUTOIONIZATION EXPERIMENT AND THEORY . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 28. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 725-741.

Y.Q. Cai, P. Storer, A.S. Kheifets, I.E. McCarthy, E. Weigold (1995). Energy-resolved momentum density of amorphous germanium and the effect of hydrogen adsorption by (e,2e) spectroscopy . Surface Science.

CAI, YQ, STORER, P, KHEIFETS, AS, MCCARTHY, IE, WEIGOLD, E(1995). ENERGY-RESOLVED MOMENTUM DENSITY OF AMORPHOUS-GERMANIUM AND THE EFFECT OF HYDROGEN ADSORPTION BY (E,2E) SPECTROSCOPY . SURFACE SCIENCE. 334. (1-3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 276-288.

VOS, M, STORER, P, CAI, YQ, KHEIFETS, AS, MCCARTHY, IE, WEIGOLD, E(1995). ELECTRONIC-STRUCTURE OF AMORPHOUS SI MEASURED BY (E,2E)-SPECTROSCOPY . JOURNAL OF PHYSICS-CONDENSED MATTER. 7. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 279-288.

Y.Q Cai, M Vos, P Storer, A.S Kheifets, I.E McCarthy, E Weigold (1995). Direct imaging of the valence electronic structure of solids by (e,2e) spectroscopy . Solid State Communications.

KHEIFETS, AS, CAI, YQ(1995). ENERGY-RESOLVED ELECTRON MOMENTUM DENSITIES OF DIAMOND-STRUCTURE SEMICONDUCTORS . JOURNAL OF PHYSICS-CONDENSED MATTER. 7. (9). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1821-1833.

KHEIFETS, AS, VOS, M(1995). SPECTRAL ELECTRON MOMENTUM DENSITY CALCULATION IN GRAPHITE . JOURNAL OF PHYSICS-CONDENSED MATTER. 7. (20). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3895-3904.

A S Kheifets, M Vos (1995). Spectral electron momentum density calculation in graphite . Journal of Physics: Condensed Matter.

P Storer, Y Q Cai, S A Canney, S A C Clark, A S Khiefets, I E McCarthy, S Utteridge, M Vos, E Weigold (1995). Surface characterization of diamond-like amorphous carbon foils by (e,2e) spectroscopy and transmission electron energy loss spectroscopy . Journal of Physics D: Applied Physics.

KHEIFETS, AS(1995). GREENS-FUNCTION CALCULATION OF THE SATELLITE SPECTRUM OF NEON . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 28. (17). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3791-3803.

STORER, P, CAI, YQ, CANNEY, SA, CLARK, SAC, KHIEFETS, AS, MCCARTHY, IE, UTTERIDGE, S, VOS, M, WEIGOLD, E(1995). SURFACE CHARACTERIZATION OF DIAMOND-LIKE AMORPHOUS-CARBON FOILS BY (E,2E) SPECTROSCOPY AND TRANSMISSION ELECTRON-ENERGY-LOSS SPECTROSCOPY . JOURNAL OF PHYSICS D-APPLIED PHYSICS. 28. (11). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2340-2344.

CAI, YQ, VOS, M, STORER, P, KHEIFETS, AS, MCCARTHY, IE, WEIGOLD, E(1995). DIRECT IMAGING OF THE VALENCE ELECTRONIC-STRUCTURE OF SOLIDS BY (E,2E) SPECTROSCOPY . SOLID STATE COMMUNICATIONS. 95. (1). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 25-29.

YARZHEMSKY, VG, KHEIFETS, AS, ARMEN, GB, LARKINS, FP(1995). LINEWIDTHS AND INTENSITIES OF SATELLITES IN PHOTOELECTRON-SPECTRA IN THE PRESENCE OF AN UNDERLYING CONTINUUM . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 28. (11). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2105-2112.

KHEIFETS, AS (1995). GREENS-FUNCTION CALCULATION OF THE SATELLITE SPECTRUM OF NEON . Journal of Physics B: Atomic, Molecular and Optical Physics.

YARZHEMSKY, VG, KHEIFETS, AS, ARMEN, GB, LARKINS, FP (1995). LINEWIDTHS AND INTENSITIES OF SATELLITES IN PHOTOELECTRON-SPECTRA IN THE PRESENCE OF AN UNDERLYING CONTINUUM . Journal of Physics B: Atomic, Molecular and Optical Physics.

M Vos, P Storer, Y Q Cai, A S Kheifets, I E McCarthy, E Weigold (1995). Electronic structure of amorphous Si measured by (e,2e) spectroscopy . Journal of Physics: Condensed Matter.

SAMARDZIC, O, KHEIFETS, AS, WEIGOLD, E, SHANG, B, BRUNGER, MJ (1995). AN (E, 2E) STUDY OF HELIUM AUTOIONIZATION EXPERIMENT AND THEORY . Journal of Physics B: Atomic, Molecular and Optical Physics.

CAI, YQ, VOS, M, STORER, P, KHEIFETS, AS, MCCARTHY, IE, WEIGOLD, E(1995). VALENCE ELECTRONIC-STRUCTURE OF POLYCRYSTALLINE SIC AS OBSERVED BY (E, 2E) SPECTROSCOPY . PHYSICAL REVIEW B. 51. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 3449-3457.

Y. Q. Cai, M. Vos, P. Storer, A. S. Kheifets, I. E. McCarthy, E. Weigold (1995). Valence electronic structure of polycrystalline SiC as observed by ( <i>e</i> ,2 <i>e</i> ) spectroscopy . Physical Review B.

M. Vos, P. Storer, S. A. Canney, A. S. Kheifets, I. E. McCarthy, E. Weigold (1994). Energy-resolved electron-momentum densities of graphite films . Physical Review B.

A. S. Kheifets, J. Lower, K. J. Nygaard, S. Utteridge, M. Vos, E. Weigold, A. L. Ritter (1994). Measurement of the spectral momentum distribution of valence electrons in amorphous carbon by ( <i>e</i> ,2 <i>e</i> ) spectroscopy . Physical Review B.

KHEIFETS, AS (1994). ON THE 2 DIFFERENT FORMS OF THE SPECTROSCOPIC FACTOR FOR THE SHAKE-UP SATELLITES . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS(1994). ON THE 2 DIFFERENT FORMS OF THE SPECTROSCOPIC FACTOR FOR THE SHAKE-UP SATELLITES . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 27. (15). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L463-L467.

KHEIFETS, AS, BRAY, I, MCCARTHY, IE, SHANG, B(1994). THEORETICAL TRIPLE DIFFERENTIAL CROSS-SECTION OF THE HELIUM ATOM IONIZATION WITH EXCITATION TO THE N=2 ION STATE . Physical Review a. 50. (6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 4700-4706.

VOS, M, STORER, P, CANNEY, SA, KHEIFETS, AS, MCCARTHY, IE, WEIGOLD, E(1994). ENERGY-RESOLVED ELECTRON-MOMENTUM DENSITIES OF GRAPHITE FILMS . PHYSICAL REVIEW B. 50. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 5635-5644.

KHEIFETS, AS, LOWER, J, NYGAARD, KJ, UTTERIDGE, S, VOS, M, WEIGOLD, E, RITTER, AL(1994). MEASUREMENT OF THE SPECTRAL MOMENTUM DISTRIBUTION OF VALENCE-ELECTRONS IN AMORPHOUS-CARBON BY (E, 2E) SPECTROSCOPY . PHYSICAL REVIEW B. 49. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2113-2120.

A. S. Kheifets, Igor Bray, I. E. McCarthy, Bo Shang (1994). Theoretical triple differential cross section of the helium atom ionization with excitation to the <i>n</i> =2 ion state . Physical Review A.

KHEIFETS, AS (1993). TRIPLE DIFFERENTIAL CROSS-SECTION CALCULATION FOR THE HELIUM AUTOIONIZATION BY ELECTRON-IMPACT . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS(1993). SATELLITE SPECTRUM OF HELIUM IN THE (GAMMA, E) AND (E, 2E) REACTIONS . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 26. (19). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L641-L645.

KHEIFETS, AS (1993). SATELLITE SPECTRUM OF HELIUM IN THE (GAMMA, E) AND (E, 2E) REACTIONS . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS(1993). TRIPLE DIFFERENTIAL CROSS-SECTION CALCULATION FOR THE HELIUM AUTOIONIZATION BY ELECTRON-IMPACT . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 26. (13). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2053-2068.

A. S. Kheifets, M. Ya. Amusia (1992). Relativistic <i>ab initio</i> calculation of the xenon 5 <i>s</i> ionization spectra for the (γ, <i>e</i> ) and ( <i>e</i> ,2 <i>e</i> ) reactions . Physical Review A.

KHEIFETS, AS, AMUSIA, MY(1992). RELATIVISTIC ABINITIO CALCULATION OF THE XENON-5S IONIZATION SPECTRA FOR THE (GAMMA, E) AND (E, 2E) REACTIONS . PHYSICAL REVIEW A. 46. (3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1261-1269.

Miron Ya Amusia (1991). HOW TO EXPLAIN THE DIFFERENCE BETWEEN (GAMMA, E) AND (E, 2E) SPECTROSCOPIC FACTORS . Australian Journal of Physics.

AMUSIA, MY, KHEIFETS, AS(1991). HOW TO EXPLAIN THE DIFFERENCE BETWEEN (GAMMA, E) AND (E, 2E) SPECTROSCOPIC FACTORS . AUSTRALIAN JOURNAL OF PHYSICS. 44. (2-3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 293-298.

Bela Shanina, A.S. Kheifets, A.I. Veinger (1991). ABSOLUTE MEASUREMENTS OF THE LOW MAGNETIC-FIELD MICROWAVE-ABSORPTION IN YBA2CU3O7-DELTA CERAMICS . Physica C: Superconductivity and its Applications.

KHEIFETS, AS, VEINGER, AI, PARITSKY, LG(1991). MAGNETIC-FLUX TRAPPING IN HOLLOW SUPERCONDUCTORS - POSSIBLE DEVICE APPLICATION FOR OPTICAL SIGNAL-DETECTION . PHYSICA C. 174. (1-3). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 86-92.

Bela Shanina, A.S. Kheifets, A.I. Veinger, L.G. Paritsky (1991). MAGNETIC-FLUX TRAPPING IN HOLLOW SUPERCONDUCTORS - POSSIBLE DEVICE APPLICATION FOR OPTICAL SIGNAL-DETECTION . Physica C: Superconductivity and its Applications.

KHEIFETS, AS, VEINGER, AI(1991). ABSOLUTE MEASUREMENTS OF THE LOW MAGNETIC-FIELD MICROWAVE-ABSORPTION IN YBA2CU3O7-DELTA CERAMICS . PHYSICA C. 177. (4-6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 289-293.

KHEIFETS, AS, VEINGER, AI(1990). LOW-FIELD MICROWAVE-ABSORPTION AND QUANTUM OSCILLATIONS IN TYPE-I SUPERCONDUCTORS . PHYSICA C. 165. (5-6). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 491-498.

Bela Shanina, A.S. Kheifets, A.I. Veinger (1990). LOW-FIELD MICROWAVE-ABSORPTION AND QUANTUM OSCILLATIONS IN TYPE-I SUPERCONDUCTORS . Physica C: Superconductivity and its Applications.

KHEIFETS, AS, VEINGER, AI, ZABRODSKII, AG, KAZAKOV, SV, TIMOFEEV, MP(1989). ON THE NATURE OF MICROWAVE-ABSORPTION IN THE SUPERCONDUCTING CERAMIC YBA2CU3O7 IN WEAK MAGNETIC-FIELDS . FIZIKA TVERDOGO TELA. 31. (1). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 294-297.

Bela Shanina (1989). ON THE NATURE OF MICROWAVE-ABSORPTION IN THE SUPERCONDUCTING CERAMIC YBA2CU3O7 IN WEAK MAGNETIC-FIELDS . Fizika Tverdogo Tela.

AMUSIA, MY, KHEIFETS, AS(1985). ON OUR ABILITY TO MEASURE THE SINGLY IONIZED RARE-GAS SPECTROSCOPIC FACTORS USING THE (GAMMA,E) AND (E, 2E) REACTIONS . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 18. (19). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L679-L684.

KHEIFETS, AS, AMUSIA, MY, YARZHEMSKY, VG (1985). ON THE VALIDITY OF THE QUASI-PARTICLE APPROXIMATION IN PHOTOELECTRON-SPECTROSCOPY . Journal of Physics B: Atomic, Molecular and Optical Physics.

KHEIFETS, AS(1985). DIFFERENCE IN THE IONIZATION SPECTRA OF ATOMS IN THE (GAMMA, E) AND (E, 2E) REACTIONS . Zhurnal Eksperimentalnoi I Teoreticheskoi Fiziki. 89. (2). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 459-469.

KHEIFETS, AS (1985). DIFFERENCE IN THE IONIZATION SPECTRA OF ATOMS IN THE (GAMMA, E) AND (E, 2E) REACTIONS . Zhurnal Eksperimentalnoi I Teoreticheskoi Fiziki.

KHEIFETS, AS, AMUSIA, MY, YARZHEMSKY, VG(1985). ON THE VALIDITY OF THE QUASI-PARTICLE APPROXIMATION IN PHOTOELECTRON-SPECTROSCOPY . JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 18. (11). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString L343-L350.

AMUSIA, MY, KHEIFETS, AS (1985). ON OUR ABILITY TO MEASURE THE SINGLY IONIZED RARE-GAS SPECTROSCOPIC FACTORS USING THE (GAMMA,E) AND (E, 2E) REACTIONS . Journal of Physics B: Atomic, Molecular and Optical Physics.

Anatoli Kheifets (1984). EFFECT OF CORRELATION PHENOMENA ON THE PHOTOELECTRON-SPECTRUM OF AN ATOM . Zhurnal Eksperimentalnoi I Teoreticheskoi Fiziki.

AMUSIA, MY, KHEIFETS, AS(1984). EFFECT OF CORRELATION PHENOMENA ON THE PHOTOELECTRON-SPECTRUM OF AN ATOM . ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI. 86. (4). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1217-1226.

AMUSIA, MY, KHEIFETS, AS(1982). THE PHOTO-ELECTRON ANGULAR-DISTRIBUTION BETA-PARAMETER IN THE REGION OF THE 3S-14P RESONANCE IN AR . PHYSICS LETTERS A. 89. (9). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 437-440.

M.Ya. Amusia, A.S. Kheifets (1982). The photoelectron angular-distribution β parameter in the region of the 3s-1 4p resonance in Ar . Physics Letters A.

M.Ya. Amusia, A.S. Kheifets (1981). The influence of “two-electron-two-hole” excitations on the 3s–14p autoionization profile in Ar atoms . Physics Letters A.

AMUSIA, MY, KHEIFETS, AS(1981). THE INFLUENCE OF 2-ELECTRON-2-HOLE EXCITATIONS ON THE 3S-14P AUTOIONIZATION PROFILE IN AR ATOMS . PHYSICS LETTERS A. 82. (8). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 407-411.

CONFERENCE PAPER

S. Yamada, T. Otobe, D. Freeman, A. Kheifets, K. Yabana(2023). Numerical experiments for exploring propagation effects in high-harmonic generation from dielectric thin films . 2023 Conference on Lasers and Electro-Optics, CLEO 2023. Institute of Electrical and Electronics Engineers Inc.

Anatoli Kheifets(2019). Time-Resolved Theory of Atomic and Molecular Photoionization for RABBITT and Attoclock . Quantum Collisions and Confinement of Atomic and Molecular Species, and Photons - Select Proceedings of the 7th Topical Conference of ISAMP 2018. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1--19. Springer

Anatoli Kheifets, Lisa Torlina, Felipe Morales, Jivesh Kaushal, Igor Ivanov, Alejandro Zielinski, Armin Scrinzi, Harm Muller, Misha Ivanov, Olga Smirnova(2015). Interpreting attoclock measurements of tunnelling times . Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString --. Optica Publishing Group

M Gisselbrecht, D Gu&#233;not, E M&#229;nsson, D Kroon, M Kotur, E W Larsen, S Kasper, M J Dahlstr&#246;m, E Lindroth, A S Kheifets, et al.(2015). Attosecond Insight into Electron Correlation . Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015. Optica Publishing Group

Anatoli Kheifets, L Zhang, Xinhua Xie, Stefan Roither, Yueming Zhou, Peixiang Lu, Xiaojun Liu, Daniil Kartashov, Markus Schoffler, Dror Shafir, et al.(2014). Attosecond spatial control of electron wave packet emission dynamics . Optics InfoBase Conference Papers. Optica Publishing Group

Probing electron correlation on the attosecond time scale @inproceedings{564e5837d5454d138bf5bbaca400107c, title = "Probing electron correlation on the attosecond time scale", abstract = "We present experimental measurements and theoretical calculations of single and double ionization time delays in various noble gases using an interferometric method. The measured delays allow us to extract information on the electron correlation.", author = "Diego Guenot and Mansson, \{Erik P\} and Anatoli Kheifets and D Kroon and M Kotur and Larsen, \{E W\} and Dahlstrom, \{J M\} and J Mauritsson and E Lindroth and Stacey Sorensen and M Gisselbrecht and Arnold, \{C L\} and A L{\^a}€{\texttrademark}Huillier", year = "2014", doi = "10.1364/HILAS.2014.HW4C.3", language = "English", isbn = "9781557529954", booktitle = "Optics InfoBase Conference Papers", publisher = "Optica Publishing Group", address = "United States", edition = "Peer Reviewed", note = "High Intensity Lasers and High Field Phenomena, HILAS 2014 ; Conference date: 01-01-2014", } . Optics InfoBase Conference Papers.

Anatoli Kheifets, Lisa Torlina, Felipe Morales Moreno, Jivesh Kaushal, Harm Muller, Igor Ivanov, Mikhail Ivanov, Olga Smirnova(2014). Attoclock measurements of strong-field ionization times . Optics InfoBase Conference Papers. Optica Publishing Group

W. C. Wallace, M. G. Pullen, D. E. Laban, A. J. Palmer, G. F. Hanne, A. N. Grum-Grzhimailo, B. Abeln, K. Bartschat, D. Weflen, I. Ivanov, et al.(2011). Above-threshold ionization in atomic hydrogen using intense few-cycle laser pulses . 2011 Int. Quantum Electr. Conf., IQEC 2011 Conf Lasers Electro-Optics, CLEO Pacific Rim 2011 Incorporating Australasian Conf. on Optics, Lasers Spectrosc. Australian Conf. Optical Fibre Technol.- Conf. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 2168--2170.

M. G. Pullen, W. C. Wallace, D. E. Laban, A. J. Palmer, G. F. Hanne, A. N. Grum-Grzhimailo, B. Abeln, K. Bartschat, D. Weflen, I. Ivanov, et al.(2011). Carrier-envelope phase effects in few-cycle ionisation of atomic hydrogen . 2011 Int. Quantum Electr. Conf., IQEC 2011 Conf Lasers Electro-Optics, CLEO Pacific Rim 2011 Incorporating Australasian Conf. on Optics, Lasers Spectrosc. Australian Conf. Optical Fibre Technol.- Conf. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 197--198.

KHEIFETS, AS(2009). Photoelectron angular correlation pattern in sequential two-photon double ionization of neon . International Conference on Multi-Photon Processes. 42. (13).

C. Bowles, M. R. Went, A. S. Kheifets, M. Vos(2006). Direct measurement of spectral momentum densities of ordered and disordered semiconductors by high energy EMS . Proceedings of the International Symposium on (e,2e), Double Photoionization and Related Topics and the 13th International Symposium on Polarization and Correlation in Electronic and Atomic Collisions. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 167--172.

Anatoli Kheifets, Thorsten Weber, R Dorner, A O Czasch, Ottmar Jagutzki, H Schmidt-Bocking, A K Muller, V Mergel, M H Prior, T Osipov, et al.(2006). Photo double ionization of fixed in space deuterium molecules . Proceedings of the XXIV International Conference. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 184--191. World Scientific Publishing Company

Anatoli Kheifets, Alexander R Dorn, G Sakhelashvili, C Hohr, Joachim Ullrich, Julian Lower, Klaus R Bartschat(2006). An (e,y2e) experiment for simultaneous ionization-excitation of helium to the He+(2P)2P states by electron impact . Proceedings of the XXIV International Conference. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 364--367. World Scientific Publishing Company

(e,3e) and (e,γ2e) Experiments: Investigations of Fundamental Four-body Coulomb Reactions @inproceedings{3af3eb5c929340df86631a53322908d1, title = "(e,3e) and (e,{\^I}³2e) Experiments: Investigations of Fundamental Four-body Coulomb Reactions", author = "Dorn, \{Alexander R\} and G Sakhelashvili and C Hohr and Anatoli Kheifets and Julian Lower and B Najjari and Schroter, \{C D\} and R Moshammer and Joachim Ullrich", year = "2003", language = "English", isbn = "0750309253", pages = "41--50", editor = "\{L.U. Ancarani\}", booktitle = "Proceedings of the International Conference on Electron and Photon Impact Ionization and Related Topics", publisher = "Institute of Physics Publishing", address = "United States", edition = "Peer Reviewed", note = "International Conference on Electron and Photon Impact Ionization and Related Topics 2002 ; Conference date: 01-01-2003", } . Proceedings of the International Conference on Electron and Photon Impact Ionization and Related Topics.

Anatoli Kheifets, Maarten Vos, Vladimir Sashin, Erich Weigold(2003). Anisotropy and Correlation Effects in the Spectral Function of Graphite as Measured by Electron Momentum Spectroscopy . X-ray and Inner-shell Processes. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 491--533. American Institute of Physics (AIP)

Anatoli Kheifets(2003). Double Photoionization: Beyond Helium Atom . Correlation and Polarization in Photonic, Electronic, and Atomic Collisions. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 37--41. American Institute of Physics (AIP)

A. Dorn, B. Najjari, G. Sakhelashvili, C. H&#246;hr, C. D. Schr&#246;ter, R. Moshammer, J. Ullrich, A. Kheifets, R. D. Dubois(2002). (e,3e) on Helium: Complete Pictures in Momentum Space . Photonic, Electronic and Atomic Collisions. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 423--428. Rinton Press

Anatoli Kheifets, Maarten Vos, Erich Weigold(2002). Electron Momentum Spectroscopy of Metals . (e,2e) Collisions with Polarized Electrons and Excited, Oriented and Spin Polarized Targets. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 70--75. American Institute of Physics (AIP)

Anatoli Kheifets, A Lahmam-Bennani, A Duguet, I Taouil, M Gaboriaud, I Avaldi, J. Berakdar(2000). Absolute Fully Resolved (e,3e) Cross Sections for the Double Ionization of Helium . The Physics of Electronic and Atomic Collisions. (1). Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 431--435. American Institute of Physics (AIP)

Cluster-assembled amorphous carbon nano-foam synthesised by high-pulse-rate laser ablation @inproceedings{4913f1e32c294c37be9e65dacfa20063, title = "Cluster-assembled amorphous carbon nano-foam synthesised by high-pulse-rate laser ablation", abstract = "We report on a new fractal amorphous carbon nano-foam with a large fraction of tetrahedrally-bonded atoms. The material was produced by high-repetition-rate laser ablation in an argon-atmosphere which resulted in a high collision frequency between carbon atoms and ions in the laser plume and argon atoms in the chamber. This creating the optimal vapor temperature and density for the efficient formation of 4-membered bonds typical of diamond. The bulk density of various foam samples is in the range whilst the specific surface area is 300–400 m2/g comparable to that of carbon aerogels. At low temperatures the as-deposited foam exhibits a strong positive electrostatic charge and non-linear current-voltage characteristics with strong hysteresis, indicative its insulating nature. After annealing, the resistivity of the foam measured at low-voltage (±30 V) is at room temperature and at 80 K, with virtually no hysteresis. The DC conductivity of this low-density carbon foam and its temperature dependence appears to be very close to that of RF-sputtered solid amorphous diamond-like carbon films.", author = "Andrei Rode and Eugene Gamaly and Rob Elliman and Anatoli Kheifets and Barry Luther-Davies", year = "1999", doi = "10.1063/1.59852", language = "English", isbn = "1563969009", pages = "512", editor = "\{Hans Kuzmany, Jorg Fink, Michael Mehring, Siegmar Roth\}", booktitle = "AIP Conference Proceedings 486", publisher = "American Institute of Physics (AIP)", note = "International Winterschool/Euroconference on Electronic Properties of Novel Materials ; Conference date: 01-01-1999", } . AIP Conference Proceedings 486.

BOOK CHAPTER

A. S. Keifets(2019). Time-Resolved Theory of Atomic and Molecular Photoionization for RABBITT and Attoclock. Quantum Collisions and Confinement of Atomic and Molecular Species and Photons. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 1-19. Springer-Nature

I. A. Ivanov and A. S. Kheifets(2013). Atoms with one and two active electrons in strong laser fields. Fragmentation Processes. Cambridge University Press

Atoms with one and two active electrons in strong laser fields @inbook{1561e8824a934074877f2d8e87ec3ddd, title = "Atoms with one and two active electrons in strong laser fields", abstract = "Introduction Recent years have witnessed a remarkable progress in high-power short laser pulse generation. Modern conventional and free-electron laser (FEL) systems provide peak light intensities of the order of 1020 W cm−2 or above in pulses in femtosecond and sub-femtosecond regimes. The field strength at these intensities is a hundred times the Coulomb field, binding the ground-state electron in the hydrogen atom. These extreme photon densities allow highly non-linear multiphoton processes, such as above-threshold ionization (ATI), high harmonic generation (HHG), laser-induced tunneling, multiple ionization and others, where up to a few hundred photons can be absorbed from the laser field. In parallel with these experimental developments, massive efforts have been undertaken to unveil the precise physical mechanisms behind multiphoton ionization (MPI) and other strong-field ionization phenomena. It was shown convincingly that multiple ionization of atoms by an ultrashort intense laser pulse is a process in which the highly non-linear interaction between the electrons and the external field is closely interrelated with the fewbody correlated dynamics [1]. A theoretical description of such processes requires development of new theoretical methods to simultaneously account for the field nonlinearity and the long-ranged Coulomb interaction between the particles. In this chapter, we review our recent theoretical work in which we develop explicitly time-dependent, non-perturbative methods to treat MPI processes in many-electron atoms. These methods are based on numerical solution of the time-dependent Schr{\"o}dinger equation (TDSE) for a target atom or molecule in the presence of an electromagnetic and/or static electric field. Projecting this solution onto final field-free target states gives us probabilities and cross sections for various ionization channels.", author = "Ivanov, \{I. A.\} and Kheifets, \{A. S.\}", note = "Publisher Copyright: {\textcopyright} Cambridge University Press 2013.", year = "2009", month = jan, day = "1", doi = "10.1017/CBO9781139017572.005", language = "English", isbn = "9781107007444", pages = "98--115", booktitle = "Fragmentation Processes", publisher = "Cambridge University Press", address = "United Kingdom", } . Fragmentation Processes.

A.S. Kheifets and M. Vos and E. Weigold (2006). Electron Momentum Spectroscopy. Analytical Characterization of Aluminum, Steel, and Superalloys. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 641-660. Taylor & Francis

Anatoli Kheifets, Maarten Vos, Erich Weigold(2006). Electron Momentum Spectroscopy . Analytical Characterization of Aluminum, Steel, and Superalloys. 1. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 641--659. Taylor \& Francis Group

C. Bowles and A.S. Keifets and V.A. Sashin and M. Vos and E. Weigold(2004). Measurement of the Valence Spectral Function of Silicon - a test of Many-body Theory. Correlation Spectroscopy of Surfaces, Thin Films, and Nanostructures. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 83-104. Willey-VCH

Anatoli Kheifets, Cameron A Bowles, Vladimir Sashin, Maarten Vos, Erich Weigold, Ferdi Aryasetiawan(2004). EMS Measurements of the Valence Spectral Function of Silicon - A Test of Many-Body Theory . Correlation Spectroscopy of Surfaces, Thin Films, and Nanostructures. 1. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 83--104. Wiley-VCH Verlag GmbH

H. Schmidt-Böking and V. Mergel and R. Dörner and H. J. Lüdde and L. Schmidt and T. Weber and E. Weigold and A. S. Kheifets (2003). Fast p-He transfer ionization processes . Many-particle quantum dynamics in atomic and molecular fragmentation.

Anatoli Kheifets, H Schmidt-Bocking, V Mergel, R Dorner, H J Ludde, L Ph H Schmidt, Thorsten Weber, Erich Weigold(2003). Fast p-He Transfer Ionization Processes: A Window to Reveal the Non-s2 Contributions in the Momentum Wave Function of Ground-State He . Many-particle Quantum Dynamics in Atomic and Molecular Frgmentation. 1. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 353--378. Springer

Anatoli Kheifets(2003). Close-Coupling Approach to Multiple-Atomic Ionization . Many-particle Quantum Dynamics in Atomic and Molecular Frgmentation. 1. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 137--151. Springer

A.S. Kheifets(2003). Close-coupling approach to multiple atomic ionization. Many-particle quantum dynamics in atomic and molecular fragmentation.

Anatoli Kheifets(2002). Close-coupling Calculations of Two-electron Atomic Ionization by Photon and Electron Impact . International Conference on Photonic, Electronic and Atomic Collisions (XXII ICPEAC). 1. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 185--196. Rinton Press

Anatoli Kheifets, A Ipatov, Igor Bray(2001). Recent progress in theory of atomic double photoionization . Many-Particle Spectroscopy of Atoms, Molcules, Clusters, and Surfaces. 1. Microsoft.AspNetCore.Mvc.Localization.LocalizedHtmlString 215--230. Kluwer Academic Publishers

OTHER

Publisher Correction @article{eeb288ca952b41e1b40e7c20d14f4c9a, title = "Publisher Correction: Imaging the square of the correlated two-electron wave function of a hydrogen molecule (Nature Communications (2017) DOI: 10.1038/s41467-017-02437-9)", abstract = "The original version of this Article contained an error in the fifth sentence of the first paragraph of the 'Application on H2' section of the Results, which incorrectly read 'The role of electron correlation is quite apparent in this presentation: Fig. 1a is empty for the uncorrelated Hartree-Fock wave function, since projection of the latter wave function onto the 2pσ u orbital is exactly zero, while this is not the case for the fully correlated wave function (Fig. 1d); also, Fig. 1b, c for the uncorrelated description are identical, while Fig. 1e, f for the correlated case are significantly different.' The correct version replaces 'Fig. 1e, f' with 'Fig. 2e and f'. This has been corrected in both the PDF and HTML versions of the Article.", author = "M. Waitz and Bello, \{R. Y.\} and D. Metz and J. Lower and F. Trinter and C. Schober and M. Keiling and U. Lenz and M. Pitzer and K. Mertens and M. Martins and J. Viefhaus and S. Klumpp and T. Weber and Schmidt, \{L. Ph H.\} and Williams, \{J. B.\} and Sch{\"o}ffler, \{M. S.\} and Serov, \{V. V.\} and Kheifets, \{A. S.\} and L. Argenti and A. Palacios and F. Mart{\'i}n and T. Jahnke and R. D{\"o}rner", note = "Publisher Copyright: {\textcopyright} 2018 The Author(s).", year = "2018", month = dec, day = "1", doi = "10.1038/s41467-018-04740-5", language = "English", volume = "9", journal = "Nature Communications", issn = "2041-1723", publisher = "Nature Research", number = "1", } . Nature Communications.

Czasch et al. reply @article{15551852e0f24dd6a9329d9efdb6941f, title = "Czasch et al. reply", author = "A. Czasch and M. Sch{\"o}ffler and M. Hattass and S. Sch{\"o}ssler and T. Jahnke and Th Weber and A. Staudte and J. Titze and C. Wimmer and S. Kammer and M. Weckenbrock and S. Voss and Grisenti, \{R. E.\} and O. Jagutzki and Schmidt, \{L. Ph H.\} and H. Schmidt-B{\"o}cking and R. D{\"o}rner and Rost, \{J. M.\} and T. Schneider and Liu, \{Chien Nan\} and I. Bray and Kheifets, \{A. S.\} and K. Bartschat", year = "2007", month = mar, day = "6", doi = "10.1103/PhysRevLett.98.109302", language = "English", volume = "98", journal = "Physical Review Letters", issn = "0031-9007", publisher = "American Physical Society", number = "10", } . Physical Review Letters.

Journal of Electron Spectroscopy and Related Phenomena @article{8baf390e681d4f63b7aa44ad07e0aabe, title = "Journal of Electron Spectroscopy and Related Phenomena: Preface", author = "Anatoli Kheifets and Maarten Vos and Cavanagh, \{Steven J.\} and Mitsuhiko Kono", year = "2005", month = jun, doi = "10.1016/j.elspec.2005.02.006", language = "English", volume = "144-147", pages = "1", journal = "Journal of Electron Spectroscopy and Related Phenomena", issn = "0368-2048", publisher = "Elsevier B.V.", } . Journal of Electron Spectroscopy and Related Phenomena.