Coverage-Dependent Adsorption Sites in the K/Ru(0001) System - a Low-Energy Electron-Diffraction Analysis
Surface Science 279(1-2): L170-L174
The two ordered phases p(2 x 2) at a coverage theta = 0.25 and (square-root 3 x square-root 3)R30-degrees at theta = 0.33 of potassium adsorbed on Ru(0001) were analyzed by use of low-energy electron-diffraction (LEED). In the (square-root 3 x square-root 3)R30-degrees phase, the K atoms occupy threefold hcp sites, while in the p(2 x 2) phase the fcc site is favoured. In both phases, the K hard-sphere radii are nearly the same and close to the covalent Pauling radius.