Theoretical Study on the Mechanism of CH + O_2 Reaction

摘要

A detailed mechanistic study of the CH + O_2 reaction, in which the products are involved, is carried out by means of CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p) + ZPVE computational method to determine a set of reasonable pathways. The reaction is shown to proceed with an exothermic barrierless addition of O_2 to the methylidyne (CH) radical to form intermediate HCOO (a2). The HCOO radical was found to have two dissociation channels, giving products P1 HCO and O radical through the nonplanar transition states, and giving intermediate CO_2H (b1) through the planar transition states, in addition to the backward reaction forming the products radical (channel A, B, C, D, E). It is shown that B (HCO + O), E (CO + OH) are the major product channels with a minor contribution from D (CO_2 + H), whereas the other channels for are less favorable.