Geometrical Structure of Graphitic Carbon on Ni(111) Studied by Extended Energy Loss Fine Structure Spectroscopy (EELFS)

Abstract

The geometry of adsorbed atoms on ordered surfaces may be determined by different experimental techniques. Among them the most used are ion scattering spectroscopy-(ISS) [1,2], surface extended X-ray absorption fine structure (SEXAFS) [3], low energy electron diffraction (LEED) [4] and normal photoelectron diffraction (NPD) [5]. All these techiques show limits in the number of possible systems to be exploited. In particular in the case of adsorbed carbon atoms the ISS suffers of low back-scattering amplitude while the carbon contamination of the optical elements [6] is the most limiting factor in SEXAFS and NPD techniques. LEED analysis is not affected by the above limits, nevertheless it requires careful and time-consuming computer analysis.