By means of the density functional theory and QCISD (Quadratic configuration interaction calculation) methods, the reaction between O(³P) and CH₂＝CHCl has been studied. The geometries for the reactants, products, intermediates and transition states have been completely optimized at UB3LYP/6-311＋＋G(d,p), UB3LYP/6-311＋＋G(3df,3pd) computational levels. All the transition states have been verified by the vibrational analysis and the internal reaction coordinate calculations. The mechanism of the reaction has been confirmed. In view of energies, the channel of forming the products CH₂＝CHO＋Cl is more favorable than the other channels.

Key words: CH₂＝CHCl, O(³P), reaction mechanism, density functional theory