H2O-catalyzed formation of O3 in the self-reaction of HO2: a computational study on the effect of nH2O (n = 1–3)

Abstract

The effect of nH₂O (n = 1–3) on the association energies of H₂O complexes and on the barriers for the formation of O₃ in the self-reaction of HO₂ reaction has been investigated by ab initio molecular orbital calculations at the modified Gaussian-2 (G2M) level of theory. The results show that H₂O can affect the complex and O₃ formation processes: the more H₂O molecules participating in the reaction, the higher stability of the association complexes and the greater the lowering of the O₃ elimination barrier becomes. For the isomers of the reactions, more hydrogen bonds being formed in the complexes enhances their stabilities. A preliminary kinetic calculation shows that below room temperature, H₂O may enhance the formation of O₃ noticeably.