title: Direct ab initio dynamics calculation of the reaction rates of CH3OCl with OH.
abstract: A direct ab initio dynamics method was carried out for the reaction CH3OCl + OH --> products. Three abstraction channels from chlorine atom, in-plane hydrogen, and out-of-plane hydrogen atoms at the CH3 group have been found. The optimized geometries and frequencies of the stationary points and the minimum-energy paths (MEPs) were calculated at the MP2/6-311G(d,p) level. To improve the reaction enthalpy and potential barrier, single-point calculations were made at three higher levels of theory, the approximate QCISD(T)/6-311++G(3df,2pd), G3, and G3(MP2) levels. Furthermore, the rate constants for three abstraction channels were evaluated using canonical variational transition state theory (CVT) with the small-curvature tunneling correction (SCT) over a wide temperature range of 220-2000 K at above three higher theory levels, respectively. The calculated rate constants as well as branching rates are in reasonable agreement with the experimental values in the temperature region 250-341 K. The present results indicate H-abstraction especially from out-of-plane hydrogen is the main reaction pathway, while Cl-abstraction is much less competitive.
authors.affiliation: Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China.
authors.forename: Hong-qing
authors.initials: HQ
authors.lastname: He
authors.forename: Jing-yao
authors.initials: JY
authors.lastname: Liu
authors.forename: Ze-sheng
authors.initials: ZS
authors.lastname: Li
authors.forename: Chia-chung
authors.initials: CC
authors.lastname: Sun