Dynamics of the CH3 + OH reaction

✍ Scribed by J. Ree; Y. H. Kim; H. K. Shin

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 535 KB
• Volume: 43
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20568

✦ Synopsis

Abstract

We study dynamics of the CH~3~ + OH reaction over the temperature range of 300–2500 K using a quasiclassical method for the potential energy composed of explicit forms of short‐range and long‐range interactions. The explicit potential energy used in the study gives minimum energy paths on potential energy surfaces showing barrier heights, channel energies, and van der Waals well, which are consistent with ab initio calculations. Approximately, 20% of CH~3~ + OH collisions undergo OH dissociation in a direct‐mode mechanism on a subpicosecond scale (<50 fs) with the rate coefficient as high as ∼10^−10^ cm^3^ molecule^−1^ s^−1^. Less than 10% leads to the formation of excited intermediates CH~3~OH† with excess vibrational energies in CO and OH bonds. CH~3~OH† stabilizes to CH~3~OH, redissociates back to reactants, or forms one of various products after intramolecular energy redistribution via bond dissociation and formation on the time scale of 50–200 fs. The principal product is ^1^CH~2~ (k being ∼10^−11^), whereas __k__s for CH~2~OH, CH~2~O, and CH~3~O are ∼10^−12^. The minor products are HCOH and CH~4~ (k∼10^−13^). The total rate coefficient for CH~3~ + OH → CH~3~OH† → products is ∼10^−11^ and is weakly dependent on temperature. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 455–466, 2011