AN EFFICIENT METHOD FOR LEED CRYSTALLOGRAPHY

Determination of periodic surface structures from analysis of LEED intensity data is usually based on the evaluation of continuous I/V-spectra for a large number of model structures for which all the structural parameters have to be refined simultaneously until the best agreement with the experimental data, as quantified by the minimum of R-factor, is achieved. It is demonstrated that analysis based on intensity data taken only at discrete energy intervals (of up to about 20 eV) leads to no loss in accuracy if compared with the evaluation of continuous I/V-spectra. The introduction of a novel RDE-factor permits in addition to replace the "grid search" technique by a "least-squares" optimisation scheme which enables automatic search of the R-factor minimum at considerably reduced computational efforts. The strength of this technique becomes particularly evident with more complex structures as is demonstrated for Ni(110)-(2 × 1)O and other systems. © 1990.