Character of the outgoing wave in soft x-ray photoemission

Bloch-waves scattering theory is applied to photoemission from Mg(0001) up to photon energies of 320 eV. The quality of various approximations to the photoemission final state is analyzed based on the Fourier decomposition of the ab initio time-reversed scattering states. The relative importance of bulk and surface photoeffect in a one-dimensional pseudopotential model and in a real crystal is studied. The crucial role of the lateral umldapp scattering at high energies is revealed, and its implications for the stationary as well as for the attosecond time-resolved photoemission are discussed. The fine structure of the photoemission intensity distribution at high energies observed in earlier experiments is reproduced and explained.