State selective population of H/sub 2/(v-italic'' = 1, J-italic'' = 1) and D/sub 2/(v-italic'' = 1, J-italic'' = 2) and rotational relaxation in collisions with H/sub 2/, D/sub 2/, and He

Journal Article · Mon Sep 01 04:00:00 EDT 1986 · J. Chem. Phys.; (United States)

OSTI ID:5522220

Meier, W; Ahlers, G; Zacharias, H

Single rotational states were populated in vibrationally excited hydrogen by stimulated Raman pumping. The population in H/sub 2/ X-italic /sup 1/summation/sup +//sub g-italic/(v-italic'' = 0,1) and D/sub 2/ X-italic /sup 1/summation/sup +//sub g-italic/(v-italic'' = 0,1) was probed state selectively by tunable vacuum ultraviolet (VUV) laser radiation around lambda = 110 nm, and the fluorescence induced when exciting the hydrogen molecules in the (0--0), (1--0), (2--0), (3--1), and (4--1) Lyman bands of the (B-italic /sup 1/summation/sup +//sub u-italic/X-italic /sup 1/summation/sup +//sub g-italic/) transition monitored. From a comparison of line heights, the stimulated Raman pumping efficiency is estimated to be 30%--50% in the focal volume. Rotational transitions in X-italic /sup 1/summation/sup +//sub g-italic/(v-italic'' = 1) were induced in collisions with H/sub 2/, D/sub 2/, and He. State-to-state rotational relaxation rates were measured for the (J-italic'' = 1..-->..J-italic'' = 3) transition in H/sub 2/(v-italic'' = 1) and for the (J-italic'' = 2..-->..J-italic'' = 0,4) transitions in D/sub 2/(v-italic'' = 1). These rates were found to be generally higher than the corresponding previously determined ones in ground state hydrogen, in qualitative accord with recent theoretical calculations. A comparison with available theoretical state-to-state cross sections shows that the rates obtained with these cross sections are generally lower than the relaxation rates directly measured in this work.

• Research Organization: Fakultaet fuer Physik, Universitaet Bielefeld, D 48 Bielfeld 1, West Germany
• OSTI ID: 5522220
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 85:5; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
DEUTERIUM
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
GASES
HELIUM
HYDROGEN
HYDROGEN ISOTOPES
ISOTOPES
LASER RADIATION
LIGHT NUCLEI
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OPTICAL PUMPING
PUMPING
RADIATIONS
RARE GASES
RELAXATION
ROTATIONAL STATES
STABLE ISOTOPES