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Author Kimura, M. ♦ Shimamura, I. ♦ Inokuti, M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ HELIUM ♦ COULOMB IONIZATION ♦ PROTONS ♦ ANTIPROTONS ♦ ATOM COLLISIONS ♦ EV RANGE 01-10 ♦ EV RANGE 10-100 ♦ TOTAL CROSS SECTIONS ♦ SEMICLASSICAL APPROXIMATION
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}.
ISSN 0094243X
Educational Use Research
Learning Resource Type Article
Publisher Date 1995-05-10
Publisher Place United States
Volume Number 334
Issue Number 1
Technical Publication No. CONF-9405132-


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