A detailed quantum chemical study is performed on the mechanism of ClOO + NO reaction at the B3LYP/6-311+G (2d) level of theory combined with CCSD (T) single point energy calculation. The possible product channels for the reaction are obtained and discussed on the basis of the singlet [ClNO3] potential energy surface. The calculation indicates that the dominant product for the title reaction is ClO + NO2 by the direct dissociation of the initial adduct, and the formation of the other products is much less likely since they are unfavorable kinetically. A comparison is also made between the title reaction and the analogous reaction of FO2 + NO to gain a deeper insight into the mechanism of the XO2 + NO reactions.

The detailed singlet potential energy surface (PES) of the [FNO3] system is investigated at B3LYP/6-311+G(2d) and CCSD(T)/6-311+G(2d) (single-point) levels. Six isomers and nine transition states are located. Various possible isomerization and dissociation channels are probed in order to explore the reaction mechanism for FO2 + NO. The calculated results indicate that the initial association between FO2 and NO can lead to the adduct FOONO, followed by the concerted F-shift and cleavage of the ON bond leading to the dominant product FNO + O2. The formation of other products, however, is much less feasible due to energy constraints. The three feasible products and reaction pathways are also analyzed for another reaction, FO + NO2, on the basis of the [FNO3] PES. This study may be helpful in understanding the reaction and chemical behaviors of oxygen fluorides.