Growth and adsorption geometry of naphthalene overlayers on HOPG studied by low-temperature scanning tunneling microscopy

We have investigated the adsorption geometries of naphthalene on the basal plane of graphite using low-temperature scanning tunneling microscopy (STM). At sub-monolayer coverage, the commensurate superstructure of (2√3 × 2√3) R30° is observed. Molecules in ordered layers are imaged with sub-molecular spatial resolution where the shape of the molecular image reflects the shape of molecular orbitals in the vicinity of the Fermi level. The multilayer films grow in a layer-by-layer mode with a superstructure described by the matrix 3 - 1 2 3 up to several monolayers. The tilted configuration of the molecule is compared with other adsorption systems.