The first-principle study on chlorine-modified silver surfaces

The properties of the Cl-modified Ag(1 1 1), (1 0 0) and (1 1 0) surfaces are studied using the first-principle density functional theory calculations with the ultrasoft pseudopotential and the generalized gradient approximation. The preferred adsorption site, relaxation of the surface structure, adsorption energy, work function change and property change with coverage are investigated. The surface relaxation of Ag(1 1 1) surface increases upon Cl modification, while those of (1 1 0) and (1 0 0) surfaces reduce. The most stable adsorption sites of chlorine atom on Ag(1 0 0) and Ag(1 1 1) are hollow ones, while that of Ag(1 1 0) is bridge site. The work function of silver surfaces increases upon Cl adsorption, as a result of electron transfer from surface to chlorine atom. The coverage effect on the adsorption energy is mainly determined by the Cl-Cl distance on the surface.