TWO-DIMENSIONAL PHASE TRANSITIONS AS STUDIED BY LEED AND AES : Xe AND Kr ADSORBED ON (0001) GRAPHITE

Abstract

This paper is a critical review of results obtained, by low energy electron diffraction and Auger electron spectroscopy, on the properties of two-dimensional phases occuring in the first layer of xenon or krypton adsorbed on (0001) graphite. It is shown that the LEED-Auger method is a suitable tool to analyse the thermodynamics, the structure, the thermal vibrations and the transition kinetics of 2 D phases. One can measure the latent heat and the entropy of the 2 D crystal formation, the binding energy between a rare gas atom and the graphite substrate. An outline of the atomic position of adsorbed atoms can also be given. At last, a mechanism of the transition 2 D gas ⇄ 2 D crystal can be taken out from the measurement of the kinetics of adsorption and desorption