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Title: Theoretical investigation of the relaxation of the bending mode of CH{sub 2}(X{sup ~}) by collisions with helium

We have earlier determined the dependence on the bending angle of the interaction of the methylene radical (CH{sub 2}) in its X{sup ~3}B{sub 1} state with He [L. Ma, P. J. Dagdigian, and M. H. Alexander, J. Chem. Phys. 136, 224306 (2012)]. By integration over products of the bending vibrational wave function, in a quantum close-coupled treatment we have calculated cross sections for the ro-vibrational relaxation of CH{sub 2}(X{sup ~}). Specifically, we find that cross sections for a loss of one vibrational quantum (v{sub b} = 2 → 1 and 1 → 0) are roughly two orders of magnitude smaller, and those for a loss of two vibrational quanta (v{sub b} = 2 → 0) four orders of magnitude smaller, than those for pure rotational relaxation. In addition, no clear cut dependence on the energy gap is seen.
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021 (United States)
  2. Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685 (United States)
  3. Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2021 (United States)
Publication Date:
OSTI Identifier:
22423766
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 21; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BENDING; COLLISIONS; CROSS SECTIONS; ENERGY GAP; HELIUM; INTERACTIONS; METHYLENE RADICALS; RELAXATION