Electron capture in collisions of O{sup 2+}({sup 3}{ital P}) ions with He atoms at energies below 10 keV: The effect of metastable O{sup 2+}({sup 1}{ital D}) ions

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.53.4164· OSTI ID:284332

Kimura, M ^[1]; Gu, J P; Hirsch, G; Buenker, R J ^[2]

---

1. Department of Allied Health Science, Yamaguchi University, Ube 755 (Japan)
2. Theoretische Chemie, Bergische Universitaet-Gesamthochschule Wuppertal, D-42097 Wuppertal (Germany)

Electron capture in O{sup 2+}({sup 3}{ital P},{sup 1}{ital D})+He collisions is studied theoretically by using a semiclassical molecular representation with six molecular channels at collision energies above 50 eV and by using a fully quantum-mechanical molecular representation with three {Pi} channels below these energies. The {ital ab} {ital initio} potential curves and nonadiabatic coupling matrix elements for the HeO{sup 2+} system are obtained from multireference single- and double-excitation configuration-interaction calculations employing a relatively large basis set. The present total cross sections for electron capture by the ground-state O{sup 2+} ions are found to be in reasonable accord with those calculated by Gargaud, Bacchus-Montabonel, and McCarroll [J. Chem. Phys. {bold 99}, 4495 (1993)] below 30 eV/u but are slightly larger above this energy. Partial cross sections for the {ital l} distribution are also slightly different. Cross sections for electron capture by the metastable O{sup 2+} ions decrease much more sharply than those for the ground-state ion as the energy is lowered, reaching a difference between them approximately as large as one to two orders of magnitude below 100 eV. The present rate coefficient for the reaction is approximately 10{sup {minus}9} cm{sup 3}/s above 10000 K, suggesting that the small rate coefficient of about 10{sup {minus}12} cm{sup 3}/s at 20000 K observed by Kwang and Fang [Phys. Rev. Lett. {bold 71}, 4127 (1993)] for electron capture by the ground-state ion might be caused, in part, by a mixture of ground and metastable ions in their experiment. {copyright} {ital 1996 The American Physical Society.}

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 284332
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 6 Vol. 53; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AB INITIO CALCULATIONS
COUPLING
CROSS SECTIONS
D STATES
ELECTRON CAPTURE
EV RANGE 10-100
EV RANGE 100-1000
GROUND STATES
HELIUM
ION-ATOM COLLISIONS
KEV RANGE 01-10
MATRIX ELEMENTS
METASTABLE STATES
OXYGEN IONS
P STATES