Generalized oscillator strengths for the valence-shell excitations of argon

Zhu, Lin-Fan; Cheng, Huadong; Yuan, Zhen-Sheng; Liu, Xiaojing; Sun, Jun; Xu, Kailai

doi:10.1103/physreva.73.042703

Cited by 26 publications

(73 citation statements)

References 38 publications

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“…Therefore, the high-energy EELS is a powerful tool to investigate the structure of atoms or molecules for the dipole-forbidden transition, but the contributions from the second-order Born term significantly influence the dynamic behavior of the dipole-allowed transition. In addition, the present work clarifies the difference between the GOSs measured by high-energy electron impact experiments and the theoretical calculations [9][10][11][12][13][14][15].…”

supporting

confidence: 73%

“…However, for other atoms, the disagreements between the experimental results and theoretical calculations in the larger momentum transfer region were generally observed [9][10][11][12][13][14][15]. These disagreements are strange because the experimental data measured by different groups [10,15] with different methods are in good agreement, while the electronic correlation is considered carefully in the calculation of random phase approximation with exchange (RPAE) [12][13][14]16,17]. Such discrepancy puzzled experimentalists and theorists for several years.…”

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confidence: 99%

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Dynamic behavior of valence-shell excitations of atomic neon studied by high-resolution inelastic x-ray scattering

Zhu

Yang

et al. 2012

Phys. Rev. A

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The high-resolution inelastic x-ray scattering has been applied to study the excitation mechanism of atomic neon. The different electric multipolar transitions of neon, i.e., the electric monopolar, dipolar, and quadrupolar ones, were clearly resolved, and their squared form factors were determined. It is found that for the monopolar and quadrupolar transitions the present inelastic x-ray scattering results are in agreement with the ones measured by high-energy electron scattering, while for the dipolar transition large discrepancies between the results measured by these two methods were observed. Such phenomena are well elucidated with the aid of the second-order Born approximation: Born amplitude of a transition near zero momentum transfer is the key factor which determines the behavior of the intramolecular multiple scattering in the high-energy electron scattering. It is revealed that the intramolecular multiple scattering in high-energy electron scattering must be considered for the dipole-allowed transition, while it is negligible for the dipole-forbidden ones.

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confidence: 73%

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confidence: 99%

Dynamic behavior of valence-shell excitations of atomic neon studied by high-resolution inelastic x-ray scattering

Zhu

Yang

et al. 2012

Phys. Rev. A

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“…Indeed, one can enhance the contribution of the nondipole parameters, since the condition ω/c q R −1 is easy to achieve. Let us note that even while neglecting the terms with q, (12) and (13) remain different: in photoionization, the angular distribution is proportional to sin 2 θ [see Eq. (12)], whereas in the inelastic scattering it is proportional to cos 2 θ [see Eq.…”

Section: Main Formulasmentioning

confidence: 99%

“…(12)], whereas in the inelastic scattering it is proportional to cos 2 θ [see Eq. (13)]. The reason for this difference is clear.…”

Section: Main Formulasmentioning

confidence: 99%

“…We demonstrate some of the advantages of fast electron scattering that already opens up the possibility to study not only dipole but also monopole and quadrupole transitions (see Refs. [12,13], and references therein). 2 Let us compare our approach to that developed in connection to the studies of the so-called (e,2e) reaction [14][15][16][17].…”

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confidence: 99%

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Angular distributions of secondary electrons in fast particle-atom scattering

2012

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We present the angular distribution of electrons knocked out from an atom in a fast charge particle collision at small momentum transfer. Not only dipole, but also quadrupole transitions determine this distribution. The contribution of these transitions can be considerably enhanced as compared to the case of photoionization. In photoionization angular distribution, the nondipole parameters are suppressed, as compared to the dipole ones, by the factor ωR/c 1, where ω is the photon energy, R is the ionized shell radius, and c is the speed of light. In fast electron-atom collisions this suppression can be considerably reduced, since the corresponding expansion parameter ωR/v 1 is much bigger than in photoionization, because the speed of the incoming electron vis much smaller than c. In formation of the angular distribution, it is decisively important that the ionizing field in the collision process is longitudinal, while in photoionization-it is transversal. We demonstrate that contrary to the case of cross sections, the angular anisotropy parameters for secondary electrons in fast charge particle-atom collisions and in photoionization are essentially different. We illustrate the general formulas by concrete results for outer s, p, and some nd subshells of multielectron noble gas atoms Ar, Kr, and Xe, at several transferred momentum values: q = 0.0, 0.1, 1.1, and 2.1. Even for very small transferred momentum q, i.e., in the so-called optical limit, the deviations from the photoionization case are prominent.

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