The role of lateral surface corrugation for the quantum dynamics of dissociative adsorption and associative desorption

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Abstract
The influence of one-dimensional lateral surface corrugation on the dissociative adsorption and associative desorption has been investigated by quantum dynamical model calculations. The study includes potential energy surfaces where either the adsorption is hindered by high barriers as in the system H2/Cu(111), or where activated as well as nonactivated paths to adsorption exist, which should be relevant for the description of, e.g., H2/Pd(100). In the high-barrier system the dynamics for normal energies below the minimum barrier height is determined by the minimum energy path, whereas at larger energies the specific distribution in the barrier height and location has a strong influence on the adsorption and desorption dynamics. At surfaces where also nonactivated paths to adsorption are present, strong quantum effects due to the wave nature of the hydrogen beam are found although sticking at such surfaces is classically possible at all incident energies. It is shown that effects usually attributed to the existence of a precursor to adsorption, i.e., sticking probabilities decreasing with increasing normal kinetic energy and increasing with increasing incident angle, can also be achieved by strong corrugation.