Variation at the surface of mean correlated displacements in fcc transition and noble metals studied by a continued fraction technique

Abstract

We calculate mean square and mean correlated displacements which are required for the determination of the Debye-Waller factors in LEED and SEXAFS experiments. The crystal model involves central and angular forces treated within the harmonic approximation. The phonon densities of states are obtained from a continued fraction method. Results concerning the mean square displacements are given for the three low index faces of fcc metals: some general trends, in agreement with experiments, are put forward. Finally, preliminary results on the mean correlated displacements between first neighbours are presented in the particular case of Cu(111).