ENHANCED SCREENING OF CORE HOLES AT TRANSITION-METAL SURFACES

Ab initio calculations based on density-functional theory were used to obtain surface core-level shifts for the 4d transition metals and silver in the initial-state model and in the full-impurity formulation, giving an unambiguous separation into initial state and screening terms. This shows that the screening of the core hole is substantially better at the surface than in the bulk for a transition metal. For Ag, an opposite and even larger effect is found, showing the central role of d-electron screening in the surface. core-level shift of the transition metals.