Intermediate ionization continua for double charge exchange at high impact energies

Journal Article · Sat May 01 00:00:00 EDT 1993 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.47.3824· OSTI ID:6873186

Belkic, D ^[1]

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1. Manne Siegbahn Institute of Physics, S-104 05 Stockholm (Sweden)

We investigate the problem of two-electron capture from heliumlike atomic systems by bare nuclei [ital Z][sub [ital P]]+([ital Z][sub [ital T]];[ital e][sub 1],[ital e][sub 2])[sub [ital i]][r arrow]([ital Z][sub [ital P]];[ital e][sub 1],[ital e][sub 2])[sub [ital f]]+[ital Z][sub [ital T]] at high incident energies, using the four-body formalism of the first- and second-order theories. Our goal is to establish the relative importance of the [ital intermediate] ionization continua of the two electrons in comparison with the usual [ital direct] path of the double electron transfer. For this purpose we presently introduce the boundary-corrected continuum-intermediate-state (BCIS) approximation, which preserves all the features of two-electron capture as a genuine four-body problem. The proposed second-order theory provides a fully adequate description of the fact that, in an intermediate stage of collision, both electrons move in the field of the two Coulomb centers. The previously devised boundary-corrected first Born (CB1) approximation can be obtained as a further simplification of the BCIS model if the invoked two-electron Coulomb waves are replaced by their long-range logarithmic phase factors defined in terms of the corresponding interaggregate separation [ital R]. The BCIS method is implemented on the symmetric resonant double charge exchange in collisions between [alpha] particles and He(1[ital s][sup 2]) at impact energies [ital E][ge]900 keV. The obtained results for the differential and total cross sections are compared with the available experimental data and satisfactory agreement is recorded. As the incident energy increases, a dramatic improvement is obtained in going from the CB1 to the BCIS approximation, since the latter closely follows the measurement, whereas the former overestimates the observed total cross sections by two orders of magnitude.

• OSTI ID: 6873186
• Journal Information: Physical Review A; (United States), Vol. 47:5; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HEAVY IONS
ION-ATOM COLLISIONS
HELIUM
ELECTRON CAPTURE
CALCULATION METHODS
CHARGE EXCHANGE
COMPARATIVE EVALUATIONS
ISOELECTRONIC ATOMS
NUCLEI
TWO-BODY PROBLEM
ATOM COLLISIONS
ATOMS
CAPTURE
CHARGED PARTICLES
COLLISIONS
ELEMENTS
EVALUATION
FLUIDS
GASES
ION COLLISIONS
IONS
MANY-BODY PROBLEM
NONMETALS
RARE GASES
664300* - Atomic & Molecular Physics- Collision Phenomena- (1992-)