The determination of surface debye temperatures from low-energy electron diffraction data

Abstract

The temperature dependence of low-energy electron diffraction (LEED) intensities has often been interpreted with kinematic theory in terms of an effective Debye temperature θ D eff of the surface atoms. The validity of this procedure, often questioned in the literature, is tested with a computer experiment in which LEED spectra are calculated from dynamical theory (layer-KKR method) for a model of Ag{111} with a given value of θ D eff and then the usual kinematic formulae are used to re-extract the value of θ D eff. The results of the experiment indicate that this procedure yields rough values of the surface Debye temperature for electron energies higher than about 40 eV, which fluctuate substantially and tend to be somewhat smaller than that originally introduced into the model. At energies lower than about 40 eV the kinematically deduced values of θ D eff are too large by 10 to 15 %.