The influence of a single water molecule on the reaction of BrO + HO2.

The influence of a single water molecule on the BrO + HO₂ hydrogen extraction reaction has been explored by taking advantage of CCSD(T)/aug-cc-pVTZ//B3LYP/6-311 + + G(d,p) method. The reaction in the absence of water have two distinct kinds of H-extraction channels to generate HOBr + O₂ (¹Δ_g) and HBr + O₃, and the channel of generation of HOBr + O₂ (¹Δ_g) dominated the BrO + HO₂ reaction. The rate coefficient of the most feasible channel for the BrO + HO₂ reaction in the absence of water is estimated to be 1.44 × 10^–11 cm³ molecule⁻¹ s⁻¹ at 298.15 K, which is consistent with the experiment. The introduction of water made the reaction more complex, but the products are unchanged. Four distinct channels, beginning with HO₂^...H₂O with BrO, H₂O^...HO₂ with BrO, BrO^...H₂O with HO₂, H₂O^...BrO with HO₂ are researched. The most feasible channels, stemming from H₂O^...HO₂ with BrO, and BrO^...H₂O with HO₂, are much slower than the reaction of BrO + HO₂ without water, respectively. Thus, the existence of water molecule takes a negative catalytic role for BrO + HO₂ reaction. [ABSTRACT FROM AUTHOR]