Adsorption of S on Ir(1Â 0Â 0) surface from first-principles calculations

Hard sphere model for S adsorption on the unreconstructed Ir(1 0 0) surface. The side views (b) and (c) are corresponding to the p(2 × 2)-S and c(2 × 2)-S hollow sites adsorption, along with the definitions of the vertical distances and bulking parameters. H, B and T in (a) denote S in hollow, bridge and top sites, respectively.