  A first principles approach, based on the real space multiple scattering
Green's function method, is presented for spin- and angle-resolved resonant
photoemission from magnetic surfaces. It is applied to the Fe(010) valence band
photoemission excited with circularly polarized X-rays around the Fe L3
absorption edge. When the photon energy is swept through the Fe 2p-3d
resonance, the valence band spectra are strongly modified in terms of absolute
and relative peak intensities, degree of spin-polarization and light
polarization dependence. New peaks in the spin-polarized spectra are identified
as spin-flip transitions induced by exchange decay of spin-mixed core-holes. By
comparison with single atom and band structure data, it is shown that both
intra-atomic and multiple scattering effects strongly influence the spectra. We
show how the different features linked to states of different orbital symmetry
in the d band are differently enhanced by the resonant effect. The appearance
and origin of circular dichroism and spin polarization are analyzed for
different geometries of light incidence and electron emission direction,
providing guidelines for future experiments.
