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Title: Double and single ionization of He by slow protons and antiprotons

Abstract

Double and single ionization of He by proton (p) and antiproton ({bar p}) impact in the energy region below 50 keV is studied theoretically using the semiclassical molecular picture. As the energy decreases, the ratio of the double to the single-ionization cross section is found to increase for {bar p} impact and to decrease for p impact. These trends are consistent with recent measurement. Ionization mechanisms differ distinctly for the p-impact and {bar p}-impact processes: For p impact,, the dominant mechanism for double ionization at the lower energies is sequential ladder climbing by the two electrons through various excited channels and finally into the continuum. For {bar p} impact, in contrast, the approaching negative charge distorts the He electron cloud toward the other side of the nucleus and decreases the electron binding energies. These effects enhance the important role of electron-electron interactions, increasing double ionization. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Authors:
 [1];  [2];  [1]
  1. Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  2. Institute of Physical & Chemical Research (RIKEN), Wako, Saitama 351-01 (Japan)
Publication Date:
OSTI Identifier:
244488
Report Number(s):
CONF-9405132-
Journal ID: APCPCS; ISSN 0094-243X; TRN: 96:012941
DOE Contract Number:  
W-31-109-ENG-38
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 334; Journal Issue: 1; Conference: 14. International IUPAP conference on few body problems in physics, Williamsburg, VA (United States), 26-31 May 1994; Other Information: PBD: 10 May 1995
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; HELIUM; COULOMB IONIZATION; PROTONS; ANTIPROTONS; ATOM COLLISIONS; EV RANGE 01-10; EV RANGE 10-100; TOTAL CROSS SECTIONS; SEMICLASSICAL APPROXIMATION

Citation Formats

Kimura, M, Department of Physics, Rice University, Houston, Texas 77251, Shimamura, I, and Inokuti, M. Double and single ionization of He by slow protons and antiprotons. United States: N. p., 1995. Web. doi:10.1063/1.48179.
Kimura, M, Department of Physics, Rice University, Houston, Texas 77251, Shimamura, I, & Inokuti, M. Double and single ionization of He by slow protons and antiprotons. United States. doi:10.1063/1.48179.
Kimura, M, Department of Physics, Rice University, Houston, Texas 77251, Shimamura, I, and Inokuti, M. Wed . "Double and single ionization of He by slow protons and antiprotons". United States. doi:10.1063/1.48179.
@article{osti_244488,
title = {Double and single ionization of He by slow protons and antiprotons},
author = {Kimura, M and Department of Physics, Rice University, Houston, Texas 77251 and Shimamura, I and Inokuti, M},
abstractNote = {Double and single ionization of He by proton (p) and antiproton ({bar p}) impact in the energy region below 50 keV is studied theoretically using the semiclassical molecular picture. As the energy decreases, the ratio of the double to the single-ionization cross section is found to increase for {bar p} impact and to decrease for p impact. These trends are consistent with recent measurement. Ionization mechanisms differ distinctly for the p-impact and {bar p}-impact processes: For p impact,, the dominant mechanism for double ionization at the lower energies is sequential ladder climbing by the two electrons through various excited channels and finally into the continuum. For {bar p} impact, in contrast, the approaching negative charge distorts the He electron cloud toward the other side of the nucleus and decreases the electron binding energies. These effects enhance the important role of electron-electron interactions, increasing double ionization. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.},
doi = {10.1063/1.48179},
journal = {AIP Conference Proceedings},
number = 1,
volume = 334,
place = {United States},
year = {1995},
month = {5}
}