VTST kinetics study of the N(2D)+O2(X3Σg−) → NO(X2Π)+O(3P,1D) reactions based on CASSCF and CASPT2 ab initio calculations including excited potential energy surfaces

We have carried out a CASSCF and CASPT2 ab initio study of the N(2D)+O2 system, that is very relevant in the upper atmosphere. The saddle points of the PESs involved in the two reactions that can occur (O(1D)+NO (1) and O(3P)+NO (2)) have been characterized. According to TST and VTST calculations performed, the N(2D)+O2 reactivity takes place through reaction (2). Also, a good agreement with the experimental kinetics data corresponding to the global deactivation of N(2D) has been obtained. These results suggest that reaction (2) dominates over the physical electronic quenching of N(2D).