Adsorption of acenes on flat and vicinal Cu(111) surfaces: Step induced formation of lateral order

The adsorption of benzene, naphthalene, and anthracene on Cu(111) and its v icinal Cu(221) and Cu(443) surfaces has been studied by means of thermal de sorption spectra (TDS) and low energy electron diffraction. For each of the studied acenes (C4n+2H2n+4, n=1,2,3) two distinct binding states were obse rved in the TDS corresponding to adsorption on terraces and at step edges. The binding energies of both states are found to increase linearly with the number of aromatic rings n. In contrast to the Cu(111) surface where these acenes form disordered adlayers only, ordered films of naphthalene and ant hracene with an alignment of the molecular axis along the steps could be pr epared on the vicinal surfaces. (C) 2001 American Institute of Physics.