Angle-Resolved Thermal Desorption and Time-of-flight spectra:Ne-Cu(111)

The angle-resolved thermal desorption flux, and time-of-flight spectrum have been computed for Ne-Cu( 111) using a microscopic description of the phonons of Cu( 1 I 1 ), and a realistic gas-solid potential. The angular distribution is narrower than cosine at 5 K, quasi-cosine at 10 K, and distinctly non-cosine at 20 and 30 K with the maximum away from the surface normal. The desorption is driven by long-wavelength phonons, but the precise angular dependence results from the temperature-dependent interplay of statistical and dynamical factors. He desorbing from graphite shows similar features.