Angle-resolved photoemission and the electronic structure of Pd(111)

A theoretical study of various models which are commonly used for the analysis of angle-resolved photoemission is reported. For the example of the Pd(111) surface we discuss the quality and justification of these models. %e have calculated the @~I-resolved surface and bulk densities of states and the band structure of occupied and unoccupied states. FurtheHIlore, we have calculated photoemission spectra within the one-step approach. These theoretical spectra reproduce the main features and trends of the experimental data. We find that the k~I-resolved densities of states are, in general, not reflected in the photoemission. The spectra can only be interpreted in a modified direct-transition model where the inf1uence of the inelastic electron-electron interaction in the final state is taken into account.