Benchmark rate constants by the hyperquantization algorithm. The F + H2 reaction for various potential energy surfaces: features of the entrance channel and of the transition state, and low temperature reactivity

In this work, we present quantum-mechanical rate constants for the prototypical reaction F +H2→HF+H for temperatures ranging from10 up to 350 K. Rate constants have been obtained by quantum scattering calculations on a very fine grid of collision energy, permitting accurate Boltzmann averaging including all the contributing partial waves. Quantum effects play a crucial role at the investigated temperatures, where the reactivity is essentially under-barrier and shows a non-Arrhenius behavior. The reaction is thus found to proceed efficiently by tunnel effect and to be enhanced by the presence of resonances.