Energy Distributions of Thermally Desorbed Molecules: NO on Ag(111) and Pt(111).

Stochastic classical trajectory simulations are employed to calculate the translational and rotational energies of NO molecules thermally desorbed from Ag(111) and Pt(111) surfaces. In all cases the mean translational and rotational energies are lower than the corresponding equilibrium values at the surface temperature. Deviation from equilibrium is much greater for desorption from silver than from platinum. Deviations are generally larger for rotational energy than for translational energy. Calculated mean rotational energies are in quantitative agreement with experiment.