Model Calculations in the Theory of Photoemission

Photoemission from several simple models describing the electronic structure of a solid in the presence of a surface is studied. Both nearly free-electron and tight-binding situations are treated, and the yield from the surface states of the latter can be calculated. For a reasonable choice of escape depth, the surface-state yield is roughly of the same magnitude as that from bulk states. With the abundance of different effects, the accent here is placed on understanding the physics involved in the photoemission process rather than on a detailed comparison with experiment. However, several approximate evaluation schemes are also presented and discussed.