NEGATIVE DIRECT RECOIL SPECTROSCOPY STUDY OF THE INITIAL OXIDATION OFTHE MG(0001) SURFACE

The submonolayer oxygen-covered Mg(0001) surface has been studied by n egative direct recoil spectroscopy (DRS) with the aim of detecting or dismissing the presence of subsurface oxygen atoms. Recorded incidence scans show that at room temperature and with the coverage of 70% of s aturation, as measured by DRS, one of two subsurface sites (oC and tA) may be populated. This supports a recent investigation of this surfac e using forward focusing of Auger electrons, where the most likely occ upied subsurface site was found to be the oC site. Furthermore, it was found that about 90% of the oxygen still remains above the surface, w hile only about 10% penetrates below the surface.