Using Monte Carlo path integral methods, calculations were made of quantum mechanical rate constants for the diffusion of H atoms on a model W(100) surface. The most interesting aspect was that it included the effect of surface atom motion on the H-atom tunneling dynamics. Although the description was fully quantum mechanical, the phonons entered the present path integral treatment in a way very similar to how they appeared in classical generalized Langevin models. The present formulation thus provided the correct quantum mechanical analogue to classical frictional effects. The principal qualitative result was that surface atom motion increased the rate of H-atom tunneling from one stable site on the surface to another.

Quantum Mechanical Rate Constants via Path Integrals: Diffusion of Hydrogen Atoms on a W(100) Surface. R.Jaquet, W.H.Miller: Journal of Physical Chemistry, 1985, 89[11], 2139-44