ACCURATE POTENTIAL-ENERGY SURFACE FOR XE/PT(111) - A BENCHMARK GAS SURFACE INTERACTION POTENTIAL

We have determined an empirical potential energy function for the interaction of xenon with the Pt(111) surface which is consistent with a wide range of dynamical and equilibrium experimental data. These include scattering measurements, with detailed angular distributions and energy transfer data, at incidence energies from 0.5 to 14.3 eV. Also used are thermal desorption rates and trapping probabilities, as well as thermodynamic properties of monolayer phases including the "energy jump" at the transition from the commensurate to the uniaxially compressed incommensurate phase. The potential also agrees with an experimental value for the frequency of vibration normal to the surface, and has the correct asymptotic behavior at large distances from the surface (V = -c3/z3, with an experimental estimate of c3). The equilibrium position for a single Xe atom lies directly above a surface platinum atom, and the calculated height above this atom is 3.35 angstrom.