Screening of the photon field in surface photoemission from simple metals

A previous two-step hydrodynamic model calculation of angle-resolved photoe mission has been improved by modeling the surface with a soft analytic func tion. The same ground state potential is used to screen the photon field an d to calculate the electronic wave functions. The implemented code can be u sed for arbitrary ground state densities along the perpendicular direction. Mathematical and physical aspects of the model are discussed extensively. The behavior of the main peak of the spectrum in response to the variation of some parameters leads us to the conclusion that the peak cannot be inter preted as the direct excitation of multipole modes. This conclusion was sug gested in the previous two-step model calculation.