THE INTERACTION OF SMALL MOLECULES WITH PD AND K-COVERED PD SURFACES AT ENERGIES FROM 200 KEV TO 6 KEV

In the energy range of 200 eV to a few keV small molecules are scatter ed al grazing incidence from Pd(110) and Pd(110) covered with a monola yer of K. The experimental setup provides ions and neutrals as primary particles and the time-of-flight analysis of the scattered particles includes both ions and neutrals. Depending on energy and K coverage, d issociation and scattering of the molecules is found. At low energies and one monolayer K the survival of H-2 is very high and decreases wit h increasing kinetic energy. At the clean surface the dissociation is high and increases with increasing energy. The data analysis shows tha t at low energies electronic processes are most important for the fate of the molecules, whether they are neutrals or ions. With increasing kinetic energy, vibrational and rotational excitations of the molecule s contribute increasingly to dissociation. Classical trajectories calc ulations reveal interesting details of these processes.