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