Double-electron capture as a two-step process

Journal Article · Sun Mar 01 04:00:00 EST 1992 · Physical Review A. General Physics; (United States)

DOI:https://doi.org/10.1103/PhysRevA.45.2965· OSTI ID:7205841

Gravielle, M S; Miraglia, J E ^[1]

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1. Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas, 1428 Buenos Aires (Argentina)

Double-electron capture by the impact of heavy projectiles on heliumlike atoms is studied with a two-electron model. The process is here considered a two-step collision, which in the frame of the distorted-wave formalism is related to the second order. This second order is evaluated by using an on-shell Green function representing one electron in each center, and it is found to be related, after some approximations, to the independent-electron model. In particular, the exact impulse approximation is used to calculate the single-capture {ital T}-matrix elements, and the electronic repulsion is included as a dynamic perturbation in first order. A configuration-interaction wave function is employed to describe the ground state of helium for double capture 1{ital s}{sup 2}{r arrow}1{ital s}{sup 2} in a He{sup 2+}-He collision. For this benchmark, differences with the use of a Hartree-Fock wave function instead are found to be negligible. Thereafter, capture to single excited states for the same system is calculated by using Hartree-Fock and variational electronic wave functions. Also, double capture for multiply charged ions on helium is calculated. Differential cross sections for double-capture He{sup 2+}-He collisions at 60 keV/amu impact energy are presented and compared with previous experiments. The present theory produces good agreement with the available data.

• OSTI ID: 7205841
• Journal Information: Physical Review A. General Physics; (United States), Journal Name: Physical Review A. General Physics; (United States) Vol. 45:5; ISSN 1050-2947; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALPHA PARTICLES
ATOM COLLISIONS
CAPTURE
CHARGED PARTICLES
COLLISIONS
DISTORTED WAVE THEORY
ELECTRON CAPTURE
ELEMENTS
FLUIDS
FUNCTIONS
GASES
GREEN FUNCTION
HELIUM
ION COLLISIONS
ION-ATOM COLLISIONS
MANY-BODY PROBLEM
NONMETALS
PROJECTILES
RARE GASES
TWO-BODY PROBLEM
WAVE FUNCTIONS