  Lubricants can affect quasicrystalline coatings surfaces by modifying
commensurability of the interfaces. We report results of the first computer
simulation studies of physically adsorbed hydrocarbons on a quasicrystalline
surface: methane, propane, and benzene on decagonal Al-Ni-Co. The grand
canonical Monte Carlo method is employed, using novel Embedded Atom Method
potentials generated from it ab initio calculations, and standard hydrocarbon
interactions. The resulting adsorption isotherms and calculated structures show
the films' evolution from submonolayer to condensation. We discover the
presence and absence of the 5- to 6-fold topological transition, for benzene
and methane, respectively, in agreement with a previsouly formulated
phenomenological rule based on adsorbate-substrate size mismatch.
