He/sup 0/ on D/sub 2/ collisions at keV energies and the HeH/sub 2/ energy surface

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

DOI:https://doi.org/10.1103/PhysRevA.31.2149· OSTI ID:5805717

Jr, Jakacky J; Pollack, E; Snyder, R; Russek, A

An experimental and theoretical study of He/sup 0/ on D/sub 2/ collisions at energies 1.0, 1.5, and 2.0 keV has been carried out to probe and to understand the energy surface of the ground electronic state of the HeH/sub 2/ triatomic molecule and of the intersections of this surface with those of low-lying electronically excited states. At each collision energy, doubly differential energy-loss spectra have been obtained and the results have been analyzed in terms of a parametric fit to an ab initio calculated ground-state energy surface. The scaled energy loss for quasielastic collisions (electronically elastic collisions with vibrational-rotational excitation) are shown to constitute a sensitive probe of the region of the ground-state energy surface in which the proximity of the He projectile breaks the H/sub 2/ (or D/sub 2/) bond. Sigmund scaling has been experimentally demonstrated to hold for the quasielastic channel in He on D/sub 2/ collisions despite the strong presence of electronically inelastic processes, a finding of particular significance, since the scaling law was derived under the assumption that there are no accessible electronically inelastic channels in the collision system. The theoretical study confirms this behavior for collisions in which electronic excitation is velocity independent and occurs in well-defined surface intersection regions. Cross sections differential in angle but integrated over all vibrotational-rotational inelastic energy losses have been both calculated and experimentally measured for the quasielastic channel, and the two are found to be in good agreement.

• Research Organization: Department of Physics, The University of Connecticut, Storrs, Connecticut 06268
• OSTI ID: 5805717
• 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

640302 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
BINDING ENERGY
BOUND STATE
COLLISIONS
CROSS SECTIONS
DEUTERIUM
DIFFERENTIAL CROSS SECTIONS
DIRECT REACTIONS
ELEMENTS
ENERGY
ENERGY LEVELS
ENERGY LOSSES
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FLUIDS
GASES
HELIUM
HELIUM COMPOUNDS
HELIUM HYDRIDES
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
LOSSES
MOLECULE COLLISIONS
NONMETALS
NUCLEAR REACTIONS
NUCLEI
ODD-ODD NUCLEI
POTENTIAL ENERGY
QUASI-ELASTIC SCATTERING
QUASI-FREE REACTIONS
RARE GAS COMPOUNDS
RARE GASES
ROTATIONAL STATES
SCATTERING
STABLE ISOTOPES
VIBRATIONAL STATES