General regularities of interaction between halogens and surface of fcc metals

Main peculiarities of chemical interaction between halogens and fcc metals have been analyzed and results for chemical reaction on copper and silver surfaces as the most studied ones are discussed. General information about the structure of adsorbed layers on metal surfaces is presented. It has been shown that halogenation occurs in two stages. First, a monolayer of chemisorbed halogen atoms is formed, and then metal halide starts to grow, forming a continuous halide film on the surface. The chlorination of silver is indicated (on the basis of the spectroscopic data) as a unique case due to the possible chlorine dissolution into the substrate bulk. It has also been shown that the use of low-energy electron diffraction is usually ineffective for identification of incommensurate lattices at the stage of monolayer and halide film structure formation. To study incommensurate surface structures and halide nucleation processes on atomic scale, probe microscopy and methods for detecting local structure are necessary.