Relativistic calculations of double<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>K</mml:mi></mml:math>-shell-photoionization cross sections for neutral medium-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Z</mml:mi></mml:math>atoms

Yerokhin, V. A.; Surzhykov, A.; Fritzsche, S.

doi:10.1103/physreva.90.063422

Cited by 4 publications

(3 citation statements)

References 29 publications

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“…Various non-linear (second- as well as higher-order perturbation) processes have been observed during the past years but could often not be calculated in good detail for many ions, atoms or molecules of interest. Well-known second-order processes of this sort include, for instance, the multi-photon absorption and emission [ 1 , 2 , 3 ], the resonant [ 4 ] and two-photon ionization [ 5 , 6 ], the radiative and double Auger emission of atoms [ 7 , 8 ] and molecules [ 9 ], their (single-photon) double ionization [ 10 , 11 , 12 ] or the Rayleigh and Raman scattering of light [ 13 , 14 , 15 ], to name just a few. Until the present, however, most of these processes are not yet (well) understood quantitatively since, in perturbation theory, each additional order (beyond the first-order) typically requires an implicit summation (integration) over the full spectrum of the system.…”

Section: Introductionmentioning

confidence: 99%

Approximate Atomic Green Functions

Fritzsche

Surzhykov

2021

Molecules

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In atomic and many-particle physics, Green functions often occur as propagators to formally represent the (integration over the) complete spectrum of the underlying Hamiltonian. However, while these functions are very crucial to describing many second- and higher-order perturbation processes, they have hardly been considered and classified for complex atoms. Here, we show how relativistic (many-electron) Green functions can be approximated and systematically improved for few- and many-electron atoms and ions. The representation of these functions is based on classes of virtual excitations, or so-called excitation schemes, with regard to given bound-state reference configurations, and by applying a multi-configuration Dirac-Hartree-Fock expansion of all atomic states involved. A first implementation of these approximate Green functions has been realized in the framework of Jac, the Jena Atomic Calculator, and will facilitate the study of various multi-photon and/or multiple electron (emission) processes.

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Section: Introductionmentioning

confidence: 99%

Approximate Atomic Green Functions

Fritzsche

Surzhykov

2021

Molecules

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“…The theoretical investigations have naturally been extended to heliumlike ions to study the competition of the Coulomb attraction of the nucleus versus the EEI as the charge of the nucleus increases [5]. With increasing nuclear charge the relativistic effects become more important [6].…”

Section: Introductionmentioning

confidence: 99%

Direct double ionization of the Ar+ M shell by a single photon

et al. 2021

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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.

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“…PMI experiments are conducted predominantly on neutral atoms and molecules ( [6][7][8][9] and references therein). Although there have been massive theoretical attempts to calculate total and differential cross sections for PMI of atoms and atomic ions with a focus on the He and Be isoelectronic sequences ( [10][11][12][13][14][15][16][17] to name just a few), experiments with ions are very scarce. Only few attempts to measure photo-double-detachment, PDD, of negative ions have been reported, and nothing for positive ions.…”

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confidence: 99%

Near- K -Edge Double and Triple Detachment of the F− Negative Ion: Observation of Direct Two-Electron Ejection by a Single Photon

Müller

Borovik

Bari³

et al. 2018

Phys. Rev. Lett.

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Double and triple detachment of the F^{-}(1s^{2}2s^{2}2p^{6}) negative ion by a single photon have been investigated in the photon energy range 660 to 1000 eV. The experimental data provide unambiguous evidence for the dominant role of direct photodouble detachment with a subsequent single-Auger process in the reaction channel leading to F^{2+} product ions. Absolute cross sections were determined for the direct removal of a (1s+2p) pair of electrons from F^{-} by the absorption of a single photon.

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Relativistic calculations of doubleK-shell-photoionization cross sections for neutral medium-Zatoms

Cited by 4 publications

References 29 publications

Approximate Atomic Green Functions

Approximate Atomic Green Functions

Direct double ionization of the Ar+ M shell by a single photon

Near- K -Edge Double and Triple Detachment of the F− Negative Ion: Observation of Direct Two-Electron Ejection by a Single Photon

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