Model potential for chemisorption: H2 + W(001)

A potential function to describe the interaction of a diatomic molecule with a solid surface is formulated as a modified London-- Eyring--Polyani--Sato (LEPS) potential. The surface is approximated by a rigid background potential, periodic in the plane of the surface. It is assumed that the individual atom--atom and atom--surface potentials are known and can be reasonably approximated by Morse functions. H2 + W(001) is presented as an example. One adjustable Sato parameter is introduced and by varying this parameter a wide range of potentials can be generated. The functional form is sufficiently simple so that classical trajectory studies of the reaction dynamics are feasible. Several illustrative trajectories are presented