Dynamical LEED analyses of the clean and the NO-adsorbed Ir(111) surface

► Clean and NO-adsorbed Ir(111) surface were studied by LEED dynamical analyses. ► Very small (1%) contraction occurs for the 1st layer of the clean Ir(111) surface. ► NO occupies the atop, fcc-hollow and hcp-hollow sites at the saturation coverage. ► The atop-NO does not dissociate but desorbs at 415 K by annealing. ► The hollow-NO partially desorbs and partially dissociates by annealing at 360K.