Free-electron final-state model and angle-resolved photoemission from a Ag(111) surface

Angle-resolved photoemission spectra from a Ag(111) surface exhibit a strong dependence on photon energy for hν extending from 11.6 to 40.8 eV that clearly demonstrates the nonvalidity of the one-dimensional density-of-states model. Trends in the positions of the peaks in the observed spectra are described within the accuracy of our computations by the initial-state band structure and a free-electron-like final state. No evidence is found for surface states nondegenerate with those of the bulk or narrowing of the bulk bands in the vicinity of the surface.