The mechanism of the reaction CH+N2 -> HCN+N

Abstract

The lowest doublet and quartet reaction surfaces of the title reaction have been studied using complete active space SCF, multireference CI, and augmented coupled cluster (CCSD (T) ) methods. Several additional intermediates and transition states have been found beyond those considered in previous work. It is found that not one but three intersystem crossings are present along one suggested ''reaction coordinate'', which also has a high barrier to reaction. It therefore seems possible that the reaction mechanism is different from what has been previously been suggested. At the highest level of theory, the reaction enthalpy at absolute zero is found to be + 3.1 kcal/mol, in excellent agreement with experiment.