Understanding adsorption geometry of organometallic molecules on graphite

To comprehensively investigate the adsorption geometries of organometallic molecules on graphene, Cp^*Ru⁺ fragments as an organometallic molecule is bound on highly oriented pyrolytic graphite and imaged at atomic resolution using scanning tunneling microscopy (STM) (Cp^* = pentamethylcyclopentadienyl). Atomic resolution imaging through STM shows that the Cp^*Ru⁺ fragments are localized above the hollow position of the hexagonal structure, and that the first graphene layer adsorbed with the fragments on the graphite redeveloped morphologically to minimize its geometric energy. For a better understanding of the adsorption site and molecular geometry, experimental results are compared with computed calculations for the graphene surface with Cp^*Ru⁺ fragments. These calculations show the adsorption geometries of the fragment on the graphene surface and the relationship between the geometric energy and molecular configuration. Our results provide the chemical anchoring geometry of molecules on the graphene surface, thereby imparting the theoretical background necessary for controlling the various properties of graphene in the future.