ANISOTROPIC TEMPERATURE FACTORS IN THE CALCULATION OF LOW-ENERGY-ELECTRON DIFFRACTION INTENSITIES

The multiple scattering theory of LEED is extended to include anisotro pic thermal vibrations. The method is based on the multipole expansion of the probability density function. This treatment of anisotropic vi brations leads to thermally averaged atomic scattering t-matrices with off-diagonal terms to be inserted in the current multiple scattering formalism. The multipole expansion allows the calculation of anisotrop ic and anharmonic vibrations. Correlation effects are neglected as in the currently used treatment of isotropic vibrations.