Adsorption of Hydrocarbons on Complex Metallic Alloy Surfaces - Lubricants and Superlubricity Renee D. Diehl, Physics, Pennsylvania State University, University Park, PA For the application of low-friction quasicrystalline surface coatings, it is important to understand the interaction between hydrocarbon lubricants and quasicrystals. We are studying the surface of an Al13Co4 alloy, which is an approximant of the Al-Ni-Co quasicrystal. We have performed a low-energy electron diffraction (LEED) experiments of this complex surface (movie, left). An extensive LEED I(E) analysis, which is an order of magnitude larger than any other LEED study, is nearly complete. This will provide input for the analysis of adsorption experiments. Surface structure model, the layer is buckled with red (blue) atoms located above (below) the plane Movie of the LEED patterns as a function of incident beam energy. Xe Benzene The adsorption of Xe was studied as a prototypical adsorbate. Xe adsorbs layer-by-layer, and does not order until the second layer begins to adsorb. The multilayer Xe appears to form a bulk-like structure which has a specific but non-symmetry alignment with the substrate. This film is observe to rotate to a symmetry direction under the influence of the electron beam, presumably due to cracking of residual gas molecules, indicating that this surface is very sensitive to contamination. Simulations are underway to gain a deeper understanding of this adsorption.