Single- and double-electron capture by 1--100-keV protons in collisions with magnesium and barium atoms

Journal Article · Sun Apr 01 04:00:00 EST 1979 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.19.1448· OSTI ID:6330464

Morgan, T J; Eriksen, F J

Absolute total cross sections for single- and double-electron capture by H/sup +/ in collisions with Mg and Ba have been measured for energies between 1 and 100 keV. The single-electron-capture cross section has also been calculated with the Gryzinski formalism of the classical binary-encounter approximation. The measured cross sections exhibit both high- and low-energy structure. The high-energy behavior is in accord with the Brinkman-Kramers results and classical predictions for the energy at which inner-shell capture becomes important. The low-energy behavior is discussed in terms of a molecular picture of the collision. The cross sections are shown to be critically dependent on curve-crossing effects which occur at avoided crossings between potential curves. At low energies the double-electron-capture cross section in Mg shows pronounced structure consistent with a description of the collision in terms of transitions via the intermediate H (1s) state. It is shown that this mechanism is not important in Ba, since curve crossings are expected to take place at internuclear separations too large for transitions to occur. A possible explanation for the decrease in single-electron-capture cross section in Ba at low energies is suggested in terms of competition from direct target-excitation collisions. For single-electron capture in Mg, recent low-energy perturbed-stationary-state calculations and high-energy classical-trajectory Monte Carlo calculations by Olson and Liu are in good agreement with experiment. The present classical binary-encounter approximation results for single-electron capture in both Mg and Ba agree with experiment to within a factor of 2 over the entire energy range. Measurements of single- and double-electron capture are also reported for Ar targets. A pronounced second maximum in the double-electron-capture cross section is found.

• Research Organization: Physics Department, Wesleyan University, Middletown, Connecticut 06457
• OSTI ID: 6330464
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 19:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALINE EARTH METALS
ARGON
ATOM COLLISIONS
BARIUM
BINARY ENCOUNTER METHOD
CAPTURE
CATIONS
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
ELECTRON CAPTURE
ELEMENTS
ENERGY RANGE
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION COLLISIONS
ION-ATOM COLLISIONS
IONS
KEV RANGE
KEV RANGE 01-10
KEV RANGE 10-100
MAGNESIUM
METALS
NONMETALS
RARE GASES
TOTAL CROSS SECTIONS