Double and single ionization of He and H{sub 2} by slow protons and antiprotons
Abstract
Double and single ionization of He and H{sub 2} by proton (p) and antiproton ({bar p})impact in the energy region below 50 keV was studied theoretically by using the semiclassical molecular picture. As the energy decreased, the ratio of the double- to the single-ionization cross section increased for impact and decreased for p impact for both He and H{sub 2}. These trends are consistent with recent measurements for He. Ionization mechanisms differ distinctly for p impact and {bar p} impact. 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 both the He and H{sub 2} electron clouds toward the other side of the nucleus and decreases the electron binding energies. These effects enhance electron-electron interactions, increasing double ionization. For the H{sub 2}, an effect of molecular orientation is an additional complication in determining the dynamics.
- Authors:
-
- Argonne National Lab., IL (United States)
- Riken, Inc., Wako, Saitama (Japan). Institute of Physical and Chemical Research
- Publication Date:
- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Org.:
- USDOE, Washington, DC (United States)
- OSTI Identifier:
- 92093
- Report Number(s):
- ANL/ER/CP-85213; CONF-941268-3
ON: DE95005828; TRN: 95:018411
- DOE Contract Number:
- W-31109-ENG-38
- Resource Type:
- Conference
- Resource Relation:
- Conference: 4. U.S./Mexico joint symposium on atomic and molecular physics, San Juan Del Rio (Mexico), 7-10 Dec 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 66 PHYSICS; HELIUM; ION-ATOM COLLISIONS; HYDROGEN; ION-MOLECULE COLLISIONS; HYDROGEN IONS 1 PLUS; ANTIPROTONS; KEV RANGE 10-100; SEMICLASSICAL APPROXIMATION; REACTION KINETICS
Citation Formats
Kimura, Mineo, Rice Univ., Houston, TX, Shimamura, Isao, and Inokuti, Mitio. Double and single ionization of He and H{sub 2} by slow protons and antiprotons. United States: N. p., 1994.
Web.
Kimura, Mineo, Rice Univ., Houston, TX, Shimamura, Isao, & Inokuti, Mitio. Double and single ionization of He and H{sub 2} by slow protons and antiprotons. United States.
Kimura, Mineo, Rice Univ., Houston, TX, Shimamura, Isao, and Inokuti, Mitio. 1994.
"Double and single ionization of He and H{sub 2} by slow protons and antiprotons". United States. https://www.osti.gov/servlets/purl/92093.
@article{osti_92093,
title = {Double and single ionization of He and H{sub 2} by slow protons and antiprotons},
author = {Kimura, Mineo and Rice Univ., Houston, TX and Shimamura, Isao and Inokuti, Mitio},
abstractNote = {Double and single ionization of He and H{sub 2} by proton (p) and antiproton ({bar p})impact in the energy region below 50 keV was studied theoretically by using the semiclassical molecular picture. As the energy decreased, the ratio of the double- to the single-ionization cross section increased for impact and decreased for p impact for both He and H{sub 2}. These trends are consistent with recent measurements for He. Ionization mechanisms differ distinctly for p impact and {bar p} impact. 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 both the He and H{sub 2} electron clouds toward the other side of the nucleus and decreases the electron binding energies. These effects enhance electron-electron interactions, increasing double ionization. For the H{sub 2}, an effect of molecular orientation is an additional complication in determining the dynamics.},
doi = {},
url = {https://www.osti.gov/biblio/92093},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Dec 31 00:00:00 EST 1994},
month = {Sat Dec 31 00:00:00 EST 1994}
}