A simple and effective procedure for the refinement of surface structure in LEED

A simple and effective procedure is described for the determination of the best-fit parameters of a given model of a surface structure by analysis of low energy electron diffraction (LEED) intensities. The procedure involves a nonlinear minimisation of χ2 for the comparison of experimental and calculated intensities as a function of the parameters of the model structure. The minimisation is carried out using the quadratic tensor model algorithm of Hanson and Krogh, which is found to have a number of advantages over more commonly used minimisation schemes. The procedure requires no changes to existing LEED code, and has therefore a quite general applicability. The results of tests of the procedure are presented for a number of surface structures that have been studied previously. These tests show that the procedure converges rapidly to the optimal values of the structural and nonstructural parameters of the surface structure.