Surface barrier bands (dotted line) for a barrier model recently proposed in the literature plotted against the surface-projected bulk band structure.

We have calculated the band structure of surface barrier states and resonances on a metal surface using a scattering approach. The theoretical states are compared with experimental results from photoemission, inverse photoemission and 2-photon emission spectroscopies. A previously proposed model of the surface barrier has been found to be grossly at variance with measured data when accurate substrate scattering is included. Information about the type of saturation of the surface potential has been found from the crystal-induced surface barrier (Shockley) state. Details of the surface barrier are required in understanding many surface phenomena including quantitative analysis of surface charge densities in scanning tunneling microscopy of surfaces.