Double-electron capture as a two-step process

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-s...

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Publicado: 1992
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10502947_v45_n5_p2965_Gravielle
http://hdl.handle.net/20.500.12110/paper_10502947_v45_n5_p2965_Gravielle
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_10502947_v45_n5_p2965_Gravielle
record_format dspace
spelling paper:paper_10502947_v45_n5_p2965_Gravielle2023-06-08T16:01:35Z Double-electron capture as a two-step process 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 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 1s21s2 in a He2+-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 He2+-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. © 1992 The American Physical Society. 1992 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10502947_v45_n5_p2965_Gravielle http://hdl.handle.net/20.500.12110/paper_10502947_v45_n5_p2965_Gravielle
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description 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 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 1s21s2 in a He2+-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 He2+-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. © 1992 The American Physical Society.
title Double-electron capture as a two-step process
spellingShingle Double-electron capture as a two-step process
title_short Double-electron capture as a two-step process
title_full Double-electron capture as a two-step process
title_fullStr Double-electron capture as a two-step process
title_full_unstemmed Double-electron capture as a two-step process
title_sort double-electron capture as a two-step process
publishDate 1992
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10502947_v45_n5_p2965_Gravielle
http://hdl.handle.net/20.500.12110/paper_10502947_v45_n5_p2965_Gravielle
_version_ 1768545017050169344

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