The energy‐dependent transmission coefficient and the energy distribution of classical particles escaping from a metastable well

We investigate the distribution of energies of thermally activated particles escaping from a metastable well. This energy distribution is connected by detailed balance to the energy‐dependent transmission coefficient, the probability that a particle injected into a well will stick. Theoretical expressions for the energy‐dependent transmission coefficient show good agreement with simulation results for a one‐dimensional reaction coordinate coupled to a frictional bath. Slight deviations from theoretical predictions based on turnover theory [E. Pollak, H. Grabert, and P. Hanggi, J. Chem. Phys. 91, 4073 (1989)] are understood in light of the assumptions of turnover theory. Furthermore, the theoretical expressions for energy distributions also provide good fits for fully three‐dimensional simulations of sticking and desorption of Ar and Xe on Pt(111) [J. C. Tully, Surf. Sci. 111, 461 (1981)]. Finally, we compare the theoretical efficiencies of several reactive flux sampling schemes, including a scheme designed to be optimal.