Fingerprinting technique in low-energy electron diffraction

The most important part in solving complex surface structures is a promising guess of the starting configuration if an automated structure refinement is employed. The “fingerprinting technique” is able to provide such information quasi-directly from experimental low-energy electron diffraction (LEED) data for a class of surface structures. The application of this method to LEED is based on the local scattering picture. Because of the short mean-free path of LEED electrons, the energy dependence of LEED intensities of fractional-order beams is mainly influenced by the local geometry of the adsorbate complex. By comparing experimental IV curves (fractional-order beams) of an unknown structure with those whose structure has been successfully analyzed, it is frequently possible to obtain information on the basic structural elements of the unknown surface system. For instance, similar IV curves suggest similar structural elements. In this paper, the fingerprinting idea will be substantiated by several representative examples