Theoretical study on reaction mechanism of the vinyl radical with nitrogen atom

The complex triplet potential energy surface of the C2H3N system is investigated at the UB3LYP and CCSD(T) (single-point) levels in order to explore the possible reaction mechanism Of C2H3 radical with N(S-4). Eleven minimum isomers and 18 transition states are located. Possible energetically allowed reaction pathways leading to various low-lying dissociation products are obtained. Starting from the energy-rich reactant C2H3 + N(S-4), the first step is the attack of the N atom on the C atom having one H atom attached in C2H3 radical and form the intermediate C2H3N(1). The associated intermediate 1 can lead to product P-1 CH2CN + H and P-2 (CH2)-C-3 + (HCN)-H-3 by the cleavage of C-H bond and C-C bond, respectively. The most favorable pathway for the C2H3 + N(S-4) reaction is the channel leading to P-1, which is preferred to that of P, due to the comparative lower energy barrier. The formation Of P-3 (C2H2)-C-3 + (NH)-N-3 through hydrogen-abstraction mechanism is also feasible, especially at high temperature. The other pathways are less competitive comparatively. (C) 2004 Elsevier B.V. All rights reserved.