Quantum chemical study on the mechanism for the reaction of C2H3 radical with O2

Ab initio UMP2 (full) method has been used to study the mechanism for the reaction of C2H3 radical with O-2 on the potential energy surface. Energies have been calculated at Gaussian-3 (G3) level. In this paper, we have optimized the geometry configuration of reactants, productions, intermediates and transition states. We have also calculated the activation energies of elementary reactions along the reaction pathways. The results suggest that the reaction mechanism of this reaction involves the formation of three-member, four-member and five-member rings and produces different reaction resultants respectively. According to the calculated activation energies, the CH2O and CHO are the main productions. At the same time, the reaction may form CH3 + CO2, CH2CO2 + H, C2H2 + O2H and COHCOH + H, etc. The probabilities gradually decrease. The reaction heats gained in our study along the four pathways (C2H3 + O-2-->CH2O + CHO, C2H3 + O-2-->CH3 + CO2, C2H3 + O-2-->C2H2 + O2H and C2H3 + O-2-->OHCOH + H) are in good agreement with those of experiments.