On the basis of ab initio and DFT theory, the ClO/ClO~- coupling system has been studied. The equilibrium geometries and harmonic frequencies of ClO/ClO~- system have been determined at B3LYP, B3P86, BLYP, BP86, BHLYP, LSDA, CCSD levels using different basis sets with diffuse and d, f polarization functions. Comparison with available experimental results is also made. The dissociation energies have been calculated using B3LYP method employing the 6-311+G(3df) basis set, and have also been corrected using the BSSE method. The intermediates and the transition state of the isomerization reaction have been found, and the bonding analysis has also been made. The results show that the main products are ClOO + Cl~- and ClOO~- + Cl for the dissociation of two coupling system. The dissociation energies for the corresponding dissociation channels are -33.39 and 82.88 kJ/mol, respectively. It should be noted that the dissociation to ClOO+Cl~- is essentially a dissociative electron transfer process with an electron transfer transition state.

Key words: density functional theory, HYPOCHLORIC ACID, REACTION MECHANISM, TRANSITION STATE, CHARGE TRANSFER REACTION, AB INITIO CALCULATION