Observation of vibrationally resolved charge transfer in H/sup +/+H/sub 2/ at E/sub CM/ = 20 eV

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · J. Chem. Phys.; (United States)

OSTI ID:6459563

Niedner, G; Noll, M; Toennies, J P; Schlier, C

The doubly differential cross sections for both the scattered protons and H atoms have been measured at E/sub LAB/ = 30 eV (E/sub CM/ = 20 eV) from theta/sub LAB/ = 0/sup 0/ to 12/sup 0/ (theta/sub CM/ = 0/sup 0/ to 18/sup 0/) for the reactions H/sup +/+H/sub 2/(v = 0)..-->..H/sup +/+H/sub 2/(v/sub f/) and ..-->..H+H/sup +//sub 2/(v/sub f/) . The energy resolution is sufficient to resolve final vibrational states in both channels. The comparison of both the angular and energy loss distributions for the two product channels provides the first clear experimental evidence of a two-step charge transfer mechanism: Vibrational excitation on the lower H/sup +/+H/sub 2/ surface is followed by charge transfer in the outgoing collision for only those H/sub 2/ molecules which are excited vibrationally high enough (v/sub f/greater than or equal to4) to overcome the endoergic barrier (..delta..E = 1.83 eV). The final vibrational distributions of H/sup +//sub 2/ appear to be very similar to those of H/sub 2/ for v/sub f/greater than or equal to4 indicating that for the angular range observed the charge transfer probability is the same for all vibrational states with v/sub f/greater than or equal to4. The comparison with classical trajectory surface hopping (TSH) calculations points to some disagreement which probably can be attributed to the potential surface used.

• Research Organization: Max Planck Institut fuer Stroemungsforschung, Bunsenstrasse 10, 3400 Goettingen, Federal Republic of Germany
• OSTI ID: 6459563
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 87:5; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
CATIONS
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
HYDROGEN
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION BEAMS
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONS
MOLECULE COLLISIONS
NONMETALS
VIBRATIONAL STATES