INTERACTIONS OF FAST N-2 MOLECULES WITH PALLADIUM SURFACES

Time-of-flight measurements of N-2 and N-2(+) scattered off clean and potassium covered Pd-surfaces indicate a collisional dissociation mech anism for kinetic energies of 250 up to 5000 eV and grazing incidence (5 degrees). Therefore, this system is predestined to be described wit hin the framework of Newton's mechanics. Classical trajectory calculat ions have been carried out using different types of interaction potent ials. It turned out that results from simulations based on pair potent ials are not in full agreement with the experimental data, so we perfo rmed additional calculations using semi-empirical potential energy sur faces, The importance of dissociation due to rotational and vibrationa l excitation respectively depends strongly on the initial molecular ax is orientation as well as on the crystallographic azimuthal direction.