The reaction mechanism of atomic oxygen radical anion (O^－) with ethylene (C₂H₄) has been investigated at the G3MP2B3 level of theory. The present calculations demonstrate that O^－ associates quickly with C₂H₄ to form ion-induced dipole complex, which can subsequently isomerize and decompose to various products, corresponding to molecular anions dissociation and associative electron detachment pathways, respectively. Based on the calculated barrier heights for various channels, the main product pathway is the associative electron detachment channel and the corresponding natural product is c-C₂H₄O; moreover, the branching ratio of molecular anion dissociation channel is smaller, and the main anion product corresponding to H₂O production channel is CH₂＝C^－ anion. The present calculations are consistent with the previous experimental results.

Key words: atomic oxygen radical anion, ethylene, reaction mechanism