title: Ab initio/density functional theory and multichannel RRKM study for the ClO + CH2O reaction.
abstract: The potential energy surface for the CH(2)O + ClO reaction was calculated at the QCISD(T)/6-311G(2d,2p)//B3LYP/6-311G(d,p) level of theory. The rate constants for the lower barrier reaction channels producing HOCl + HCO, H atom, OCH(2)OCl, cis-HC(O)OCl and trans-HC(O)OCl have been calculated by TST and multichannel RRKM theory. Over the temperature range of 200-2000 K, the overall rate constants were k(200-2000K) = 1.19 x 10(-13)T(0.79) exp(-3000.00/T). At 250 K, the calculated overall rate constant was 5.80 x 10(-17) cm(3) molecule(-1) s(-1), which was in good agreement with the experimental upper limit data. The calculated results demonstrated that the formation of HOCl + HCO was the dominant reaction channel and was exothermic by 9.7 kcal/mol with a barrier of 5.0 kcal/mol. When it retrograded to the reactants CH(2)O + ClO, an energy barrier of 14.7 kcal/mol is required. Furthermore, when HOCl decomposed into H + ClO, the energy required was 93.3 kcal/mol. These results suggest that the decomposition in both the forward and backward directions for HOCl would be difficult in the ground electronic state.
authors.affiliation: Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Tian
authors.forename: Wen-Mei
authors.initials: WM
authors.lastname: Wei
authors.forename: Zhi-Mei
authors.initials: ZM
authors.lastname: Tian
authors.forename: Hong-Yi
authors.initials: HY
authors.lastname: Yang
authors.forename: Tian-Jing
authors.initials: TJ
authors.lastname: He
authors.forename: Fan-Chen
authors.initials: FC
authors.lastname: Liu
authors.forename: Dong-Ming
authors.initials: DM
authors.lastname: Chen