A computational investigation on the mechanism of the reaction between O(1D) and NF3

The mechanism of the reaction between O(1D) and NF3, experimentally studied by spectroscopic techniques [V.I. Sorokin, N.P. Gritsan, A.I. Chichinin, J. Chem. Phys. 108 (1998) 8995], has been investigated at the Coupled Cluster level of theory in conjunction with double-zeta and triple-zeta quality basis sets. The process commences by the exoergic (105.4 kcal mol−1) formation, on the singlet surface, of the O–NF3 intermediate, whose eventual dissociation into NF2 and OF passes through the isomerization to F2N–OF. The energy barrier of this process, 58.8 kcal mol−1, is significantly lower than the intersystem crossing from the singlet O–NF3 to the triplet O(3P) and NF3 dissociation products. This is consistent with the experimental observation that, in the reaction between O(1D) and NF3, the unreactive quenching to O(3P) represents only a minor reaction channel.