Velocity dependence of the cross sections for Penning and associative ionization of H and D atoms by He(2 /sup 3/S) metastable atoms

Journal Article · Wed Nov 01 04:00:00 EST 1978 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.18.2063· OSTI ID:6853615

Fort, J; Laucagne, J J; Pesnelle, A; Watel, G

The velocity dependence of both the Penning and associative ionization cross sections sigma/sub PI/ and sigma/sub AI/ for the He(2 /sup 3/S) + H interacting system as well as total ionization cross section sigma/sub TI/ is measured for the relative velocity range 1900--5300 m/sec (0.015--0.10 eV energy range) in a crossed-beam experiment by a time-of-flight technique. Characteristic cross-section ratios sigma/sub AI//sigma/sub TI/ and the relative magnitudes of the cross sections sigma/sub AI/, sigma/sub PI/, and sigma/sub TI/ are reported. The experimental results concerning the total ionization cross section are in very good agreement with previous theoretical work, but the experimental values of the ratio sigma/sub AI//sigma/sub TI/ are found to be higher than theoretical values, especially at low energies. A numerical solution of the Schroedinger equation with a complex potential is performed to interpret both the results on the He(2 /sup 3/S) + H system and our previously published results on the He(2 /sup 1/S) + H system. A truncated width is used for the calculation of the associative cross sections. It is observed that an exponentially shaped autoionization width GAMMA (R) = Ae/sup -R//B is satisfactory and that the width for the He(2 /sup 1/S) + H system is nearly equal to the width for the He(2 /sup 3/S) + H system.

• Research Organization: Service de Physique Atomique, Centre d'Etudes Nucleaires de Saclay, Boite Postale 2, 91190 Gif sur Yvette, France
• OSTI ID: 6853615
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 18:5; 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
ATOM-ATOM COLLISIONS
ATOMIC BEAMS
BEAMS
COLLISIONS
CROSS SECTIONS
CRYOGENIC FLUIDS
DEUTERIUM
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
HELIUM
HYDROGEN
HYDROGEN ISOTOPES
IONIZATION
ISOTOPES
LIGHT NUCLEI
METASTABLE STATES
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PENNING EFFECT
RARE GASES
STABLE ISOTOPES
VELOCITY