TITLE

Comprehensive theoretical studies on the CF3H dissociation mechanism and the reactions of CF3H with OH and H free radicals

AUTHOR(S)
Meiling Zhang; Zijing Lin; Ce Song
PUB. DATE
January 2007
SOURCE
Journal of Chemical Physics;1/21/2007, Vol. 126 Issue 3, p034307
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The potential energy surfaces for the CF3H unimolecular dissociation reaction and reactions of CF3H with free radical OH and H were investigated at the B3LYP/6-311++G** and QCISD(T)/6-311++G** levels and by the G3B3 theory. All the possible stationary and first-order saddle points along the reaction paths were verified by the vibrational analysis. The calculations account for all the product channels. The reaction enthalpies obtained at the G3B3 level are in good agreement with the available experiments. Canonical transition-state theory with Wigner tunneling correction was used to predict the rate constants for the temperature range of 298–2500 K without any artificial adjustment, and tshe computed rate constants for elementary channels can be accurately fitted with three-parameter Arrhenius expressions. The theoretical rate constants of the CF3H+H reaction agree with the available experimental data very well. The theoretical and experimental rate constants for the CF3H+OH reaction are in reasonable agreement. The H abstraction of CF3H by OH is found to be the main reaction channel for the CF3H fire extinguishing reactions while the CF3H unimolecular dissociation reaction plays a negligible role.
ACCESSION #
23836713

 

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