Theoretical study on the Br + CH3SCH3 reaction

✍ Scribed by Hui Zhang; Gui-Ling Zhang; Li Wang; Bo Liu; Xiao-Yang Yu; Ze-Sheng Li

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 249 KB
• Volume: 28
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.20646

✦ Synopsis

Abstract

The multiple‐channel reactions Br + CH~3~SCH~3~ → products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6‐31+G(d,p) level, and energetic information is further refined by the G3(MP2) (single‐point) theory. The rate constants for every reaction channels, Br + CH~3~SCH~3~ → CH~3~SCH~2~ + HBr (R1), Br + CH~3~SCH~3~ → CH~3~SBr + CH~3~ (R2), and Br + CH~3~SCH~3~ →CH~3~S + CH~3~Br (R3), are calculated by canonical variational transition state theory with small‐curvature tunneling correction over the temperature range 200–3000 K. The total rate constants are in good agreement with the available experimental data, and the two‐parameter expression k(T) = 2.68 × 10^−12^ exp(−1235.24/T) cm^3^/(molecule s) over the temperature range 200–3000 K is given. Our calculations indicate that hydrogen abstraction channel is the major channel due to the smallest barrier height among three channels considered, and the other two channels to yield CH~3~SBr + CH~3~ and CH~3~S + CH~3~Br are minor channels over the whole temperature range. © 2007 Wiley Periodicals, Inc. J Comput Chem 2007