FLAT SURFACE STUDY OF THE ELEY-RIDEAL DYNAMICS OF RECOMBINATIVE DESORPTION OF HYDROGEN ON A METAL-SURFACE

The dynamics of a direct reaction between a gas phase H atom and an adsorbed H atom, often referred to as an Eley-Rideal mechanism, is explored using a fully three-dimensional flat surface model for Cu(111). The model is based on a flat-surface approximation for a single electronically adiabatic potential energy surface (PES). This reduces the inherently six-dimensional reactive scattering problem (for a rigid surface) to a three-dimensional problem by introducing three constants of motion. The resulting scattering problem is treated quantum mechanically by solving the time-dependent Schrödinger equation, and also by quasiclassical trajectory calculations. We have considered four different model PESs which are all more or less compatible with available knowledge about the interactions between hydrogen atoms and molecules and Cu(111). We have studied the dependence of the reactive cross section and product translational energy and rovibrational state distributions on the kinetic energy and angle of the incident H atom, and the vibrational state of the adsorbed H atom. © 1995 American Institute of Physics.