Rotational relaxation in supersonic beams of hydrogen by high resolution photoelectron spectroscopy

Journal Article · Mon Nov 15 00:00:00 EST 1982 · J. Chem. Phys.; (United States)

OSTI ID:7040100

Pollard, J E; Trevor, D J; Lee, Y T; Shirley, D A

The rotational relaxation of n-H/sub 2/, p-H/sub 2/, HD, and n-D/sub 2/ in a free jet expansion was studied by means of rotationally resolved photoelectron spectroscopy using a collimated supersonic molecular beam. Rotational state distributions were determined from the relative intensities of the Q branch rotational components for a wide range of stagnation pressures with nozzle temperatures from 300 to 700 K. Significant deviations from a Boltzmann distribution were observed for those cases in which the degree of rotational relaxation was substantial. HD was found to relax after undergoing only one-tenth of the number of collisions required to relax H/sub 2/ or D/sub 2/. The state-to-state rate constants method of Rabitz and Lam was used to model the relaxation of p-H/sub 2/ and was confirmed to be quite effective in accounting for the experimentally observed population distributions.

• Research Organization: Materials and Molecular Research Division, Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720
• OSTI ID: 7040100
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 77:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY LEVELS
EXCITED STATES
HIGH TEMPERATURE
HYDROGEN
JETS
MEDIUM TEMPERATURE
MOLECULAR BEAMS
NONMETALS
PHOTOELECTRON SPECTROSCOPY
RELAXATION
ROTATIONAL STATES
SPECTROSCOPY