Quantum-mechanical and impact-parameter treatment of He/sup 2 +/-H collisions

Journal Article · Mon Apr 01 04:00:00 EST 1985 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.31.2227· OSTI ID:5759768

van Hemert, M C; van Dishoeck, E F; van der Hart, J A; Koike, F

Charge-transfer (sublevel) cross sections for He/sup 2 +/ + H collisions have been calculated in the 20-eV--to--10-keV center-of-mass energy region. Both a time-independent quantum-mechanical close-coupling method (20--500 eV) and a semiclassical impact-parameter method (0.1--10 keV) were used. The close-coupling formalism is developed in terms of a molecular-state description of the HeH/sup 2 +/ system and is extended to include both radial and rotational couplings. The potentials and radial and rotational couplings for the 2ssigma, 2psigma, 3dsigma, and 2p..pi.. molecular states were computed by expressing the molecular orbitals as variationally determined linear combinations of Slater-type orbitals centered at the atoms. Common molecular-electron translation factors were introduced to ensure proper asymptotic behavior of the wave functions and were found to be crucial for agreement between calculated and experimental cross sections. The usual practice of compensating for the neglect of these factors by using couplings evaluated at an atomic origin rather than at the center of mass of the nuclei is analyzed. Quantum-mechanical and semiclassical results are compatible only if Coulomb trajectories instead of straight-line trajectories are used. In particular the sublevel cross section for He/sup +/(2p/sub plus-or-minus1/) production is found to be extremely sensitive to the trajectory. At all energies above 50 eV radial and rotational couplings are about equally important. Below 100 eV cross sections fall off rapidly, and radiative charge transfer becomes the dominant process below 25 eV.

• Research Organization: Department of Physical Chemistry, Gorlaeus Laboratories, University of Leiden, P.O. Box 9502, 2300 RA Leiden, Netherlands
• OSTI ID: 5759768
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 31:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
ELECTRON-ELECTRON COUPLING
ELEMENTS
ENERGY RANGE
EV RANGE
EV RANGE 10-100
EV RANGE 100-1000
HELIUM IONS
HYDROGEN
IMPACT PARAMETER
ION COLLISIONS
ION-ATOM COLLISIONS
IONS
KEV RANGE
KEV RANGE 01-10
LCAO METHOD
MECHANICS
NONMETALS
QUANTUM MECHANICS
SLATER METHOD
TRAJECTORIES