Core-electron binding-energy shifts at surfaces

A first-principles calculation of a surface-binding-energy shift has been done for the $3s$ orbital of Cu(100). Both initial- and final-state effects are found to be important to the binding-energy shift. Surface and bulk screening lengths around the core holes are small relative to the near-neighbor distance. The surface-binding-energy shift is 0.36 eV, which is consistent with experimental data on noble metals. The relaxation shift is -0.30 eV.