Abstract

Thermal desorption spectroscopy (TDS) experiments provide a natural point of contact between experimental and computational surface physics. Two main issues are involved in the correct calculation of TDS spectra: i) full statistical mechanics treatment of desorption and ii) accurate quantum mechanical description of the electronic and ionic degrees of freedom. In this talk I will discuss both issues. First I will present a formulation that allows the calculation of the absolute rate of desorption with no statistical mechanics approximation. The method is applied to the desorption of water on the MgO(001) surface in the low coverage limit, using density functional theory as the underlining quantum mechanics method. Then I will discuss how to include nuclear quantum effects and how to refine the calculations using more accurate quantum Monte Carlo techniques, using thermodynamic integration to compute chemical potentials.