Capture of polarized electrons during scattering of He+-ions from clean and Mn-covered Fe(100)-surfaces

We have investigated the emission of polarized light after capture of spin polarized electrons in glancing-angle collisions of 15 keV He+-ions with th e surface of clean Fe(100) and ultrathin Mn films grown on Fe(100) at diffe rent temperatures. The intensity of fluorescence light emitted in the HeI 2 (3)S - 3(3)P, lambda = 388.9 nm transition shows oscillations with Mn cover age, as observed in the intensity of reflected projectiles. The spin polari zation of captured electrons shows a pronounced decrease upon deposition of Mn and vanishes for coverages > 0.5 ML. The polarization of orbital moment a increases upon deposition of Mn. Based on neutral fractions after grazing scattering of 20 keV Na+-ions this is attributed to a decrease in work fun ction. (C) 1999 Elsevier Science B.V. All rights reserved.