Electronic excitation in collisions of H sub 2 sup + on He

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Physical Review, A; (USA)

DOI:https://doi.org/10.1103/PhysRevA.42.6436· OSTI ID:6144820

Furlan, R J; Russek, A ^[1]

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1. Department of Physics, The University of Connecticut, Storrs, CT (USA)

{ital Ab} {ital initio} cross sections have been calculated for electronic excitation resulting from single collisions in the keV energy range between H{sub 2}{sup +} initially in the ground electronic and vibrational state incident on He targets. These collisional excitation studies are based on {ital ab} {ital initio} calculations of the three lowest adiabatic states of the (HeH{sub 2}){sup +} quasimolecular system and {ital ab} {ital initio} calculations of the nonadiabatic gradient coupling matrix elements between these three adiabatic states. With use of straight-line trajectories in the classical trajectory approximation, cross sections have been obtained for (1) charge exchange into the ground state of He and (2) collisional dissociation via electronic excitation 1{sigma}{sub {ital g}}{r arrow}1{sigma}{sub {ital u}} of the H{sub 2}{sup +} projectile. Furthermore, with a knowledge of the diabatic structure of the (HeH{sub 2}){sup +} energy levels, (3) the sum of the cross sections for Rydberg excitation of the He target or Rydberg excitation of the H{sub 2}{sup +} projectile or charge exchange into the repulsive state of H{sub 2} was also obtained. The calculated cross sections are in reasonable agreement with available experimentally measured cross sections. The energy thresholds for these cross sections are found to be determined by excitation at level crossings between the ground electronic state and the H{sub 2}{sup +}(1{sigma}{sub {ital u}})+He(1{ital s}{sup 2}) at {ital R}{approx equal}1.2 a.u. and the H{sub 2}{sup +}(1{sigma}{sub {ital g}})+He(1{ital s},2{ital l}) at {ital R}{approx equal}0.7 a.u.

• OSTI ID: 6144820
• Journal Information: Physical Review, A; (USA), Journal Name: Physical Review, A; (USA) Vol. 42:11; ISSN 1050-2947; 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
CATIONS
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DISSOCIATION
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUIDS
GASES
HELIUM
HYDROGEN IONS
HYDROGEN IONS 2 PLUS
ION COLLISIONS
ION-ATOM COLLISIONS
IONS
KEV RANGE
MOLECULAR IONS
NONMETALS
RARE GASES