Circularly polarized photon emission spectroscopy of keV ions scattering off (un-)magnetized surfaces

To study the interaction of 2-15 keV He ⁺ ions with (un-)magnetized surfaces we use the degree of circular polarization of photons emitted by the neutralized ions. The general features of the relation between circular polarization and the magnetic substate distributions of the neutralized particles are indicated. They provide the basis for discussing the results obtained for a magnetized Fe(110) single crystal. Different models are discussed and used to understand at least qualitatively the general trends in the measured data.