Core-level shifts for Au epitaxial overlayers on Ag

The Au 4$f_{7/2}$ core-level binding energies for epitaxial Au films on Ag(111) and Ag(100) and Ag-covered Au films have been determined from photoemission measurements. The surface and subsurface contributions can be separated, and the evolution of binding energies as a function of Au film thickness provides useful information about the one-electron potential variation within the film. The mode of initial film growth is determined by the core-level intensities from different layers.