Adsorption of rare-gas atoms on microsurfaces of large aromatic molecules

The binding of rare-gas (R) atoms to large aromatic molecules (M) on the one hand and to the basal plane of graphite on the other hand represents two extremes of the interaction of rare-gas atoms with ordered arrays of sp² hybridized carbon atoms. In this paper we discuss the analogies between the characteristics of large van der Waals M·R_n complexes and R atoms on graphite surfaces, focusing on structure, packing, orientational registry effects, and the nuclear motion of R adsorbates on finite microsurfaces. The elucidation of the structure, energetics, and nuclear dynamics of large M·R_n complexes rests on semiempirical model calculations of potential surfaces. These provide a quantitative account of the geometry, the existence of isomers, the dissociation energies, and the frequencies of out-of-plane and in-plane vibrational modes for large-amplitude intermolecular nuclear motion.