SURFACE-PLASMON SPECTROSCOPY - PHOTOELECTRON-SPECTRA FROM ADSORBATES ON ALUMINUM

The adsorption of small molecules on polycrystalline aluminium films is studied with X-ray Photoelectron Spectroscopy by observing the surface and interface plasmon satellites. Therefore we systematically analyse the coupling with the surface plasmons of core level photoelectrons, issued from the metal, the oxygen and/or other adsorbed molecules (carbon monoxide, sulfur hexafluoride, and n-decane). We show indeed that aluminium surface plasmon satellites can be selectively observed in the energy loss structures associated with the core level photoelectron peaks of adsorbed species. In the case of aluminium covered with oxygen for instance, the intensity of the surface plasmon is regularly transferred from 11 to 8 eV: this is observed on the Al 2p and O 1s core levels, but also, in an original way, behind the F 1s or C 1s levels from SF6, CO, or, n-decane molecules adsorbed on the metallic surface. The potentialities of the results are discussed, and other developments of the technique are proposed. © 1979.