Selective vibrational excitation and mode conservation in H/sup +/+CO/sub 2//N/sub 2/O inelastic and charge transfer collisions

Journal Article · Sat Aug 15 00:00:00 EDT 1987 · J. Chem. Phys.; (United States)

OSTI ID:6400755

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

Total angular distributions and vibrationally resolved time-of-flight spectra have been measured for H/sup +/+CO/sub 2//N/sub 2/O at collision energies of 9.8 and 30 eV and scattering angles up to theta = 15/sup 0/. Results are available for the scattered protons as well as for H atoms from charge transfer collisions into the electronic ground states of CO/sup +//sub 2//N/sub 2/O/sup +/. For both systems, the H/sup +/ and H product channels exhibit practically identical total angular distributions with marked rainbow structures in the CO/sub 2/ case. The time-of-flight distributions, on the other hand, reveal strongly selective excitation of the ..nu../sub 3/ fundamental modes and their overtones for both target molecules and both product channels. In addition, at each scattering angle, the ..nu../sub 3/ transition probability distributions for CO/sub 2/ and N/sub 2/O are remarkably similar to those for CO/sup +//sub 2/ and N/sub 2/O/sup +/, respectively. The dominance of the ..nu../sub 3/ mode excitation in the neutral molecules is in accord with what is expected from the combination of dipole- and valence-type interaction mechanisms on the lower H/sup +/+CO/sub 2//N/sub 2/O potential energy surfaces. Excitation of the same mode with nearly the same distributions in the charge transfer channel is explained by Franck--Condon selection rules, which favor transitions between identical vibrational states of either CO/sub 2/ and CO/sup +//sub 2/ or N/sub 2/O and N/sub 2/O/sup +/.

• Research Organization: Max-Planck-Institut fuer Stroemungsforschung, D-3400 Goettingen, Federal Republic of Germany
• OSTI ID: 6400755
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 87:4; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ATOMIC IONS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
DISTRIBUTION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FRANCK-CONDON PRINCIPLE
HYDROGEN IONS
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONS
MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
OXIDES
OXYGEN COMPOUNDS
SELECTION RULES
TIME-OF-FLIGHT METHOD
VIBRATIONAL STATES