The reaction mechanism of OCIO with OH has been studied using the B3LYP/6-311 + G* * and the high-level electron-correlation CCSD(T)/6- 311 + G* * at single-point. The results show that four products of HOC! + O_2, HC1 + O_3, CIO + HO_2 and HOCIO2 can be obtained by association, H-shift and dissociation. In view of energy, the channels to yield H0C1 + O_2 and HC1 + O_3 are more favorable, but the route to products CIO + HO2 is kinetically most difficult.

Key words: DFT, TRANSITION STATE THEORY, HYPOCHLORIC ACID, OXYGEN, ASSOCIATION, REACTION MECHANISM