On the reaction of ground-state nitrogen atoms with bromomethyl radicals: A computational study

Abstract

A computational study of the reaction of N( 4S) with CH 2Br radicals has been carried out. The reaction starts through the formation of a relatively stable intermediate which does not involve an energy barrier. The two most exothermic products are those resulting from the release of a bromine atom, H 2C = N + Br and trans-HC = NH + Br. A kinetic study, within the framework of the statistical theories, shows that the most exothermic product, namely H 2C = N + Br, is also the preferred product under kinetic control, whereas only minor fractions of HBrCN + H are predicted at all temperatures. Therefore, the mechanistic characteristics observed for the N( 4S) + CH 2Br reaction are very similar to the N( 4S) + CH 2Cl reaction, but quite different from those found in the case of N( 4S) + CH 2F, where the preferred channel corresponds to formation of HFCN through elimination of a hydrogen atom. The rate coefficient for the title reaction is estimated to be about 9 × 10 −13 cm 3 s −1 molecule −1 at 300 K, showing that should proceed with a high efficiency.