Regensburg 2000 – scientific programme
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O: Oberflächenphysik
O 11: Postersession (Eröffnung)
O 11.112: Poster
Monday, March 27, 2000, 19:00–22:00, Bereich C
The interaction of CO with C2H4 or Cs on Cu(111) observed by friction with the conduction electrons. — •Matthias Hein1, Paul Dumas2, Andreas Otto1, and G Williiams2 — 1Heinrich-Heine-Universität Düsseldorf, Lehrstuhl für Oberflächenwissenschaft, Universitätsstraße. 1, 40225 Düsseldorf — 2LURE and LASIR-CNRS, Centre Universitaire Paris Sud, F-91405 Orsay Cedex, France, EU
Simultaneous measurements of the changes in the DC resistance and IR reflectivity of thin epitaxial copper (111) films have been performed during co-adsorption of CO with ethylene or Cesium. The linear dependence of these two quantities, which has previously been observed for CO on Cu(111) films, does also hold for the various adsorbates used in this study. Importantly, we have shown that the linearity factor is independent of the adsorbate type, as predicted by theory. CO-adsorption of CO with C2H4 or Cs results in changes in IR reflectance and in resistance which are larger than the sum of the individual changes induced by adsorption of corresponding quantities of the single species. The CO-ethylene results are interpreted as a consequence of covalent through-metal bonding of the adsorbates via the lowest unoccupied molecular orbitals. The Cs-CO results cannot be understood with this model, and a tentative explanation is given.