Implementation of the CCGM approximation for surface diffraction using WignerRhyphen;matrix theory

摘要

The CCGM approximation for surface scattering proposed by Cabrera, Celli, Goodman, and Manson lsqb;Surf. Sci.19, 67 (1970)rsqb; is implemented for realistic surface interaction potentials using WignerRhyphen;matrix theory. The resulting procedure is highly efficient computationally and is in no way limited to hard wall or purely repulsive potentials. Comparison is made with the results of closehyphen;coupling calculations of other workers which include the same diffraction channels in order to fairly evaluate the CCGM approximation which is an approximation to the coupled channels Lippmanndash;Schwinger equation for theTmatrix. The shapes of selective adsorption features, whether maxima or minima, in the scattered intensity are well represented in this approach for cases in which the surface corrugation is not too strong.