A three-dimensional quantum mechanical study of the F + H₂/D₂ reactions. On a new potential energy surface

We report quantum mechanical cross sections and rate constants for the title reactions, as calculated on the Stark-Werner potential energy surface. The calculations, carried out in the reagents arrangement channel by employing negative imaginary potentials, were done within the coupled-state approximation. The calculated cross sections were compared with quasi-classical trajectory calculations. The calculated rate constants for the two title reactions as well as their isotopic ratio were found to be in good agreement with experiment. Part of the study is devoted to showing the existence of strong tunneling processes caused by a thin potential barrier.