Elucidation of the O(1D)+HF → F+OH mechanism by means of quasiclassical trajectories

The dynamics and mechanism of the O(D-1) + HF -> F + OH reaction have been studied through quasi-classical trajectory calculations carried out on the 1(1)A' Potential Energy Surface (PES) fitted by Gomez-Carrasco et al. [Chem. Phys. Lett., 2007, 435, 188]. The influence of the collision energy and the initial rovibrational state on the reaction has been considered. As a result of this study, we conclude that for v = 0 the reactive collisions take place exclusively through an indirect mechanism that involves a long-lived complex. Interestingly and somewhat unexpectedly for a barrierless reaction, vibrational excitation causes a large enhancement of the reactivity due to the concurrence of a direct abstraction mechanism. Unlike other reactions also taking place on a barrierless PES featuring deep wells, no insertion mechanism is observed in O(D-1) + HF reactive collisions.