Multielectron inner-shell photoexcitation in absorption spectra of Kr: Theory and experiment

Schaphorst, Stephen J.; Kodre, Alojz; Ruscheinski, Johannes; Crasemann, Bernd; Åberg, T.; Tulkki, Jukka; Chen, Mau Hsiung; Azuma, Y.; Brown, G. S.

doi:10.1103/physreva.47.1953

Cited by 106 publications

(88 citation statements)

References 90 publications

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“…X-ray absorption of pure elements, revealing the minute details of the absorption edge profile and of the multielectron excitations in the near-edge energy region, provides a thorough check of the theoretical models of the atomic system [1]. The absorption coefficient in this region is modified also by the scattering of the photoelectron on the atomic surroundings (XAFS = X-ray absorption fine structure).…”

Section: Introductionmentioning

confidence: 99%

X-ray absorption in atomic potassium

Gomilšek

Kodre

Arčon

et al. 2008

Nuclear Instruments and Methods in Physics Research Section B:

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A new high-temperature absorption cell for potassium vapor is described. X-ray absorption coefficient of atomic potassium is determined in the energy interval of 600 eV above the K edge where thresholds for simultaneous excitations of 1s and outer electrons, down to [1s2p] excitation, appear. The result represents also the atomic absorption background for XAFS (X-ray absorption fine structure) structure analysis. The K ionization energy in the potassium vapor is determined and compared with theoretical data and with the value for the metal.

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Section: Introductionmentioning

confidence: 99%

X-ray absorption in atomic potassium

Gomilšek

Kodre

Arčon

et al. 2008

Nuclear Instruments and Methods in Physics Research Section B:

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“…A monatomic sample is readily available for elements of noble gas family: indeed, X-ray absorption spectra in the vicinity of K-and L-edges have been studied for most elements of the group [1][2][3][4][5]. The experimental data are used as a test for successive approximations in the theoretical calculation of photoabsorption cross-section.…”

Section: Introductionmentioning

confidence: 99%

A double cell for X-ray absorption spectrometry of atomic Zn

Mihelič

Kodre

Arčon

et al. 2002

Nuclear Instruments and Methods in Physics Research Section B:

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A high-temperature cell with a double wall design has been constructed for X-ray absorption spectrometry of metal vapors. The inner cell, assembled from a corundum tube and thin plates without welding or reshaping, serves as a container of the vapor sample. It is not vacuum tight: instead, the outer tube provides inert atmosphere. Several spectra of K-edge atomic absorption of Zn were obtained in the stationary working regime below the Zn boiling point. The Kedge profile shows an extremely strong resonance and, above the continuum threshold, coexcitations of the outer electrons. Ó 2002 Elsevier Science B.V. All rights reserved.PACS: 78.70.Dm; 39.90.+d Keywords: X-ray atomic absorption; Zn vapor; Zn K-edge Absorption spectrometry of elements in monatomic state is of continuous interest in atomic physics and in structural analysis. A monatomic sample is readily available for elements of noble gas family: indeed, X-ray absorption spectra in the vicinity of K-and L-edges have been studied for most elements of the group [1][2][3][4][5]. The experimental data are used as a test for successive approximations in the theoretical calculation of photoabsorption cross-section. The details of the edge shape and tiny sharp features on the smooth monotonous decrease of the cross-section with energy -the multielectron excitations -reveal some peculiarities of the coupling schemes and configuration interaction in these atoms [6,7].Apart from noble gases, few elements can be prepared in a monatomic gas state. The volatile elements mostly form bi-or polyatomic molecules, the non-volatiles require complex high-temperature Nuclear

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“…This is the main reason why up to now multiple atomic excitations involving inner-shell electron were studied only by absorption spectroscopy. Since they are relatively easy to manipulate experimentally, and handle theoretically, noble gas atoms have been investigated in detail [7][8][9][10][11]. An inherent problem of absorption studies remains proper separation of the dominating single-electron photoionization component underlying a weak multielectron signal.…”

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Separation of Two-Electron Photoexcited Atomic Processes near the Inner-Shell Threshold

et al. 2009

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By means of a high resolution resonant inelastic x-ray scattering spectroscopy, we have for the first time separated spectral features pertaining to different two-electron atomic processes in the vicinity of an innershell threshold. Contributions of shakeoff, shakeup, and resonant 1s3p double excitations were extracted from the Ar KM-M 2;3 M x-ray satellite line intensity measured as a function of photon energy from ½1s3p double excitation threshold to saturation. The isolated ½1s3pnln 0 l 0 excitation spectrum is critically compared to the outcome of the multiconfiguration Dirac-Fock model with relaxation.According to the nature of photon-electron interaction a photon is absorbed only by a single electron. On the other hand, photoionization of an inner-shell electron is sometimes accompanied by removal of another electron (shakeoff) or its excitation into a higher empty atomic level (shakeup), and below the double photoionization threshold, doubly excited atomic states can be created. These multielectron excitations are straightforward manifestations of the breakdown of the independent electron picture as they appear due to the electron-electron interactions. Despite the persistent and intensive research the mechanisms of electron-electron correlations have not been fully elucidated yet. While the well-known shake mechanism (governed by monopole transitions between relaxed states) is commonly taken as a synonym for the double photoionization or excitation process, the presence of dynamical effects in the near-threshold region makes the interpretation of double photoexcitation spectra much more complicated.The main experimental problem hindering the study of near-threshold multielectron excitations is the overlap of the shakeoff, shakeup, and double excitation spectral contributions. Strong dependence of the shakeoff to shakeup probability ratio on the atomic number and atomic shell was employed to bypass this difficulty in some special cases. While the shakeup mechanism fully dominates the electron excitation following 1s photoionization of Be [1], the shakeoff prevails in the 1s2p double photoionization of mid-Z atoms [2]. It was found that a time-dependent perturbation theory [3] describes well the double photoionization of outer-shell electrons in low-Z atoms; for inner shells and higher Z atoms significant deviations were found [4,5], indicating that other mechanisms besides the shakeoff are at work. In the latest work a semiclassical knockout effect was suggested to dominate the near-threshold double 1s photoionization in 3d transition metals [6].One of the most interesting multielectron features is double excitations exhibiting discrete resonances in the preedge region. These processes are extremely weak when both electrons are excited from core levels, but they become more probable if a valence electron takes part in the excitation. In such cases structural solid-state effects obscure spectral details related to multiple atomic excitations, limiting such studies to gaseous atomic targets. This is the mai...

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Multielectron inner-shell photoexcitation in absorption spectra of Kr: Theory and experiment

Cited by 106 publications

References 90 publications

X-ray absorption in atomic potassium

X-ray absorption in atomic potassium

A double cell for X-ray absorption spectrometry of atomic Zn

Separation of Two-Electron Photoexcited Atomic Processes near the Inner-Shell Threshold

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