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

The dynamics and mechanism of the O( 1 D) + 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 Gómez-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( 1 D) + HF reactive collisions. A barrierless PES featuring a deep well where no insertion mechanism is found and vibrational excitation triggers a direct abstraction mechanism.