Kinetic Monte Carlo simulations of temperature programed desorption of O/Rh(111)

We present a kinetic Monte Carlo simulation based on ab initio calculations for the thermal desorption of oxygen from a Rh(lll) surface. Several models have been used for the parametrization of the interaction between the adsorbed atoms. We find that models based on a parametrization with only pairwise interactions have a relatively large error in the predicted adsorption energies. This error can be significantly reduced by including three-and four-body interactions. In addition, we find that a significant amount of atoms adsorb in a second adsorption site - the hep-hollow site - at an elevated temperature. Consequently, only a many-body multisite model of the oxygen interactions yields appropriate desorption spectra for the full coverage range, while more simple models only capture the correct shape in the low-coverage case. Our parametrization allows us to predict the adsorption energies of an arbitrary configuration of adsorbates with a mean average error of less than 6 meV/atom.