Theoretical calculations on the reaction of ethylene with oxygen

The triplet potential energy surface for the reaction of ethylene with molecular oxygen in the ground state has been calculated at the QCISD(T, full)/6-311++G(3df,2p)//MP2(full)/6-311G(d,p) level of theory. Four intermediates and 17 transition states are located along the minimum energy reaction path. Six major radical product channels are revealed, namely, C2H3 + HO2, O(3P) + C2H4O, H + C2H3O2, OH + C2H3O, OH + CH3CO, and O(3P) + CH3CHO. In view of reaction barrier heights, the dominant channels are predicted to be C2H3 + HO2, O(3P) + C2H4O, H + C2H3O2, and C2H4O2(3A″). The calculated rate constants for the abstraction reaction path are in good agreement with the available experimental data. The implication of the current results in the initiation of the combustion of ethylene is discussed.