Molecular angular momentum reorientation of electronically excited hydrogen ( B sup 1. Sigma. sup + sub u )

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458671· OSTI ID:6424782

Pibel, C D; Moore, C B ^[1]

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1. Department of Chemistry, University of California, Berkeley, CA (USA)

The room temperature rate constants for molecular angular momentum reorientation of H{sub 2}, HD, and D{sub 2} ({ital B} {sup 1}{Sigma}{sup +}{sub {ital u}}, {ital v}{prime}=0, {ital J}{prime}=1, {ital M}{sub {ital J}{prime}}=0) in collisions with He, Ne, Ar and H{sub 2} ({ital X} {sup 1}{Sigma}{sup +}{sub {ital g}}) have been measured. The effective cross sections for changing {ital M}{sub {ital J}{prime}} in collisions of H{sub 2}, HD, D{sub 2} with He and Ne were found to be about 30 A{sup 2} and were nearly the same for each isotope and with He and Ne as collision partners. The measured He--H{sub 2}({ital B}) reorientation cross section is about 50% larger than the cross section calculated with a simple semiclassical model using a potential that approximates the {ital ab} {ital initio} data for the H{sub 2}({ital B})--He potential energy surface. The cross sections for reorientation of HD and D{sub 2} in collisions with Ar were found to be 10.6{plus minus}2.0 and 13.9{plus minus}3.0 A{sup 2}, respectively. The smaller cross section is due to the dominant role played by quenching of the electronic energy of molecular hydrogen in collisions with Ar. The reorientation of D{sub 2}({ital B}) in collisions with room temperature H{sub 2}({ital X}) occurs with a 7.6{plus minus}3.4 A{sup 2} cross section. The small cross section for reorientation of the angular momentum is again due to the dominance of quenching in the collision dynamics.

• OSTI ID: 6424782
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 93:7; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
640304 -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR MOMENTUM
ARGON
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
CROSS SECTIONS
DEUTERIDES
DEUTERIUM
DEUTERIUM COMPOUNDS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
HELIUM
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN DEUTERIDE
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MOLECULE COLLISIONS
NEON
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORIENTATION
RARE GASES
STABLE ISOTOPES