Role of rotational motion in the dissociative adsorption/associative desorption dynamics of H2 (D2) on surfaces: Steering and dynamical quantum filtering
Abstract
It is well known that molecules have to be oriented in a certain way before certain reactions involving these molecules could proceed on surfaces, and such orientation preferences ultimately determine how the molecule dynamically responds to the orientation dependence of the potential energy (hyper-) surface (PES) which describes the interaction between molecules and surfaces. In general, for the interaction of H2 with single-crystal metal surfaces (e.g., Al, Fe, Ni, Cu, Ru, Rh, Pd, Ag, W, Pt, Au), the H-H bond orientation parallel to the surface is preferred over perpendicular orientation.
In this contribution, we shall mainly discuss the dynamics involved in dissociative adsorption and associative desorption, which represent the initial and the final stages in any reaction. Dissociative Adsorption is the initial process by which we can utilize the surface as a catalyst, or medium, and initiate the reaction of two reactants that may otherwise even be, normally, too stable to interact with each other. Associative Desorption, on the other hand, is a means by which we can harvest the resulting products of the reaction from the surface. In particular, we concentrate on the dissociative adsorption and associative desorption dynamics of hydrogen at copper and palladium surfaces.
