The adsorption of xenon on Ru(1 0 1̄ 0): an angle-resolved UV photoemission study

Recently, we examined the interaction of xenon with a ruthenium(1 0 1̄ 0) surface between 29 and 300 K and determined adsorbed phases, binding states as well as adsorption/desorption kinetics and work function changes. Here we present our UV photoemission results, which support and complement the previous results and shed light on the electronic structure of the adsorbed Xe phases. Up to the completion of the first monolayer we observe the typical 4d and 5p emissions of a single Xe species: The Xe 5p1/2 and 4d3/2 signals appear at a binding energy of 7.33 and 63.5 eV below EF, respectively. Other emissions due to adsorption at step sites or to two-dimensional phase transitions (solid–gas) were not observed, indicating a good surface homogeneity in agreement with our previous findings. In the entire Xe coverage range studied, we note an mj splitting of the Xe 5p3/2 level, which is particularly pronounced around the first monolayer coverage. In this saturated monolayer phase, we find a mutual Xe distance of 4.2 (±0.1) Å, in analogy to our previous LEED results. A detailed comparison between the saturated (compressed) monolayer (Θ=1.0) and the relaxed monolayer (Θ=0.95) is performed, and our data are discussed in view of the properties of one- and two-dimensionally ordered systems known from the literature.