State-to-state measurements of internal rotational predissociation in OH--Ar ([ital A] [sup 2][Sigma][sup +])
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 (United States)
Internal rotational predissociative levels of OH--Ar ([ital A] [sup 2][Sigma][sup +]) have been identified lying up to 350 cm[sup [minus]1] above the OH [ital A] [sup 2][Sigma][sup +] ([ital v]=0, 1)+Ar dissociation limit. The predissociative level energies, lifetimes, and OH [ital A] [sup 2][Sigma][sup +] rotational product distributions have been measured. Complexes prepared in many of these predissociative levels are long lived with lifetimes [ge]50 ps. A novel variation of stimulated emission pumping has enabled quantitative OH [ital A] [sup 2][Sigma][sup +] rotational distributions to be obtained following OH--Ar predissociation. The OH product distributions are highly selective. The highest energetically available channel is always populated, yet in many cases, low rotational levels are conspicuously absent. The OH--Ar predissociative levels have been assigned nearly good quantum numbers based on a rotational contour analysis of the predissociative features and/or the OH [ital A] [sup 2][Sigma][sup +] rotational product distributions. A two-step mechanism involving Coriolis coupling and the potential anisotropy has been proposed to describe the predissociation process. A comparison between the experimentally measured and theoretically calculated observables provides a guide for further refinements of the OH [ital A] [sup 2][Sigma][sup +]+Ar potential energy surface.
- OSTI ID:
- 7171633
- Journal Information:
- Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:4; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
74 ATOMIC AND MOLECULAR PHYSICS
ARGON COMPLEXES
COMPLEXES
CORIOLIS FORCE
DISSOCIATION
ENERGY
ENERGY LEVELS
EXCITED STATES
HYDROXYL RADICALS
POTENTIAL ENERGY
PREDISSOCIATION
QUANTUM NUMBERS
RADICALS
ROTATIONAL STATES