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Quantum calculations of unusual mode specificity in H+C[sub 2]H[sub 2][r arrow]H[sub 2]+C[sub 2]H

Journal Article · · Journal of Chemical Physics; (United States)
DOI:https://doi.org/10.1063/1.468060· OSTI ID:6909115
;  [1]
  1. Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)

We report reduced dimensionality coupled channel scattering calculations of rotationally averaged cross sections for the H+C[sub 2]H[sub 2][leftrightarrow]H[sub 2]+C[sub 2]H reaction. A new ten degree-of-freedom potential is developed for use in these calculations. This potential surface is based on a previous potential for C[sub 2]H[sub 2] and C[sub 2]H as well as previous [ital ab] [ital initio] calculations of the saddle point properties. We focus on the effect of exciting the symmetric and antisymmetric CH stretches, and symmetric CC stretch in C[sub 2]H[sub 2] on the reactivity, and also on the vibrational distribution of the H[sub 2] and C[sub 2]H products. A significant and surprising finding is that excitation of the CC stretch in combination with excitation of either the symmetric and/or antisymmetric stretch increases the reactivity significantly. A simple Franck--Condon model is used to rationalize these mode specific effects. The thermal rate constant for the H[sub 2]+C[sub 2]H[r arrow]H+C[sub 2]H[sub 2] reaction is also calculated in the temperature range from 200 to 400 K, and compared to limited experimental data.

DOE Contract Number:
FG05-86ER13568
OSTI ID:
6909115
Journal Information:
Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:10; ISSN JCPSA6; ISSN 0021-9606
Country of Publication:
United States
Language:
English