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Title: Two-step mechanisms in ionization-excitation of He studied by binary (e,2e) experiments and second-Born-approximation calculations

Abstract

An electron momentum spectroscopy study on ionization-excitation processes of He is reported. The symmetric noncoplanar (e,2e) cross sections for transitions to excited ion states have been measured relative to that to the ground ion state at impact energies of 1240 and 4260 eV. The experimental results exhibit a marked dependence on the impact energy. This provides strong evidence that higher-order effects are involved. Second-Born-approximation calculations are performed and their results are compared with the experimental ones. It is shown that the two-step mechanisms play crucial roles in the ionization-excitation processes.

Authors:
; ;  [1];  [2];  [3]
+ Show Author Affiliations
  1. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)
  2. Department of Nuclear Physics and Quantum Theory of Collisions, Faculty of Physics, Moscow State University, Moscow 119992 (Russian Federation)
  3. Nuclear Physics Institute, Moscow State University, Moscow 119992 (Russian Federation)
Publication Date:
OSTI Identifier:
20982519
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevA.75.052701; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; BORN APPROXIMATION; CROSS SECTIONS; ELECTRON-ATOM COLLISIONS; ELECTRONS; EXCITATION; EXCITED STATES; GROUND STATES; HELIUM; IONIZATION; IONS; KEV RANGE 01-10; SPECTROSCOPY

Citation Formats

Watanabe, N., Takahashi, M., Udagawa, Y., Kouzakov, K. A., and Popov, Yu. V. Two-step mechanisms in ionization-excitation of He studied by binary (e,2e) experiments and second-Born-approximation calculations. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.052701.
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Watanabe, N., Takahashi, M., Udagawa, Y., Kouzakov, K. A., & Popov, Yu. V. Two-step mechanisms in ionization-excitation of He studied by binary (e,2e) experiments and second-Born-approximation calculations. United States. doi:10.1103/PHYSREVA.75.052701.
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Watanabe, N., Takahashi, M., Udagawa, Y., Kouzakov, K. A., and Popov, Yu. V. Tue . "Two-step mechanisms in ionization-excitation of He studied by binary (e,2e) experiments and second-Born-approximation calculations". United States. doi:10.1103/PHYSREVA.75.052701.
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@article{osti_20982519,
title = {Two-step mechanisms in ionization-excitation of He studied by binary (e,2e) experiments and second-Born-approximation calculations},
author = {Watanabe, N. and Takahashi, M. and Udagawa, Y. and Kouzakov, K. A. and Popov, Yu. V.},
abstractNote = {An electron momentum spectroscopy study on ionization-excitation processes of He is reported. The symmetric noncoplanar (e,2e) cross sections for transitions to excited ion states have been measured relative to that to the ground ion state at impact energies of 1240 and 4260 eV. The experimental results exhibit a marked dependence on the impact energy. This provides strong evidence that higher-order effects are involved. Second-Born-approximation calculations are performed and their results are compared with the experimental ones. It is shown that the two-step mechanisms play crucial roles in the ionization-excitation processes.},
doi = {10.1103/PHYSREVA.75.052701},
journal = {Physical Review. A},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
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Journal Article:
DOI:  10.1103/PHYSREVA.75.052701
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  • - Phys. Rev. A; (United States)
    A modification is proposed to the kinematical description of a binary-encounter collision, taking into account the p-dependent (p is the initial momentum of the target electron) kinetic energy lost by the slow (ejected) electron while propagating out of the atomic potential. It is shown, at least for the high-energy asymmetric (e,2e) reaction on helium, that this correction leads to a ''universal'' representation of the data and to a remarkable agreement with experiment over a wide range of ejection energies and scattering angles.

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