β Scribed by G Benitez; JM Heras; L Viscido
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The adsorption of oxygen by thin cobalt films supported on oxidized Sit 100) was studied at 300 K using Auger electron spectroscopy (AES) and work function changes (Acpl. The films were prepared in separate UHVsystems either by vapor deposition (PVDI or by pulsed laser ablation (PLA). The oxygen saturation exposure depends on the preparation method: in PVD-films at least 100 L are needed, while in films deposited by PLA only 70 L are required. However, films prepared by PLA, but on cleaved muscovite, showed uptake curves saturating at x 80 L as in evaporated films. The work function changes upon oxygen adsorption showed an initial increase of 0.2 eV, followed by a steep decrease, saturating at = -1.2 eV. An oxide formation is clearly demonstrated by the AES MVV spectra of Co at exposures above 9 L.
π SIMILAR VOLUMES
Hydrogen, oxygen and cesium adsorption on beryllium metal were modelled using a Bed5 cluster containing seven layers. The ab initio'Hartree-Fock calculations employ effective core potentials and full Dgi, point-group symmetry. Cesiation of the surface is found to lower the work function by 2.2 eV, i