Abstract: B3LYP/6-311++G** and MP2/6-311++G** calculations were used to analyze the interaction between thioperoxy radical (HSO) and ozone (O3) in gas-phase, which are of interest in atmospheric chemistry. The results showed that there were three equilibrium geometries (complexes I, II, and III) at the B3LYP/6-311++G** level, but only one stable configuration (complexes II) at MP2/6-311++G** level. And all the equilibrium geometries were confirmed to be stable states by analytical frequency computations. Complexes I and III use the 1H atom of HSO as proton donor and the terminal 4O atom of O3 as acceptor to form red shift hydrogen bond systems. However, complex II uses the same proton donor and acceptor to form a blue shift hydrogen bond system. Interaction energies of the complexes corrected with basis set superposition error (BSSE) and zero point vibrational energy (ZPVE) lie in the range from -3.37 to -4.55 kJ·mol-1 at B3LYP/6-311++G** level. The natural bond orbital (NBO) and atoms in molecules (AIM) theories were also applied to explain the structures and the electron density topology properties of the three hydrogen bond complexes.

Key words: Thioperoxy radical, Ozone, Hydrogen bond interaction, NBO theory, AIM theory