Directional photoemission of polarized electrons from adsorbate systems

A theory of angle-resolved spin-polarized photoemission is applied to a localized adatom-level on W(001). For unpolarized light, substantial spin-polarization effects are found, which depend sensitively on the position of the adatom relative to the substrate. The intensities produced by left- and righthand circularly polarized light exhibit a sizeable asymmetry.