A theoretical investigation of the two lowest potential energy surfaces for the reaction C(³P)+NO (²Π)

The two lowest potential energy surfaces for C(³P)+NO(²Π) have been investigated. The stationary points were first located using CASSCF gradient calculations and the geometries reoptimized using complete active space second-order perturbation theory. Zero-point corrections have been included in the energetics. In addition to the three linear conformations CNO, NCO and CON, a previously unreported triangular conformation has been found. We found no barrier to carbon attack to the oxygen end of NO, leading to CON. This channel would lead to direct production of N+CO but is expected to be entropically disfavoured. No barrier to CNO formation has been found, in accord with experimental predictions. Experimentalists found no evidence of CO production and concluded that CN+O are the main products, but our investigation gives no reason to exclude formation of N+CO. It is suggested that the discrepancy may be due to the fact that no monitoring of CO production was performed.