Ab Initio Study of the Oxidation Reaction of CO by ClO Radicals

The oxidation of carbon monoxide by ClO radicals was studied by ab initio molecular orbital theory calculations. Geometry optimizations and vibrational frequencies were computed using two methods: Møller−Plesset second-order perturbation theory (MP2), and quadratic configuration interaction in the space of single and double excitations (QCISD). Single-point energy calculations were performed at the QCISD level with triple excitations treated perturbatively (QCISD(T)) and the aug-cc-pVTZ basis set. Canonical transition state theory was used to predict the rate constants as a function of temperature (550−2500 K), and three-parameter Arrhenius expressions were obtained by fitting to the computed rate constants. The possible impact of the title reaction in combustion chemistry is also discussed.