Abstract
Surface layers of chemisorbed chlorine were obtained on the (111) face of a silver single crystal by decomposition of ethylene dichloride vapour. The structure of the surface was investigated by LEED and the concentration was estimated and controlled by Auger-electron spectroscopy. The formation of two surface structures, corresponding to different amounts of chemisorbed chlorine was observed. At lower coverages a (√3×√3)–R30° superstructure, which is stable up to high temperatures, was found. At higher surface concentrations, a (3×3) superstructure was formed, which was stable in ultra-high vacuum up to about 200°C. Models of the two structures are proposed in qualitative agreement with the experimental results.