Japanese Journal of Applied Physics · 1974 · 10 citations · 0 references
Natural SciencesChemistryPhysicsPhysical ChemistrySurface ChemistrySurface ScienceAb Initio MethodsAdsorption At InterfacesChemical BondingMolecular BondingSurface AdsorptionSurface PhysicsAdsorption EnergiesAdsorption MechanismsAdsorption PhenomenaAdsorption SitesBonding OrbitalsCoulomb InteractionSurface Adsorption SitesValence Band
The adsorption of CO on the diamond (111) surface is calculated using the Extended Hückel Theory with a modification to take into account the effect of the Coulomb interaction energy at the atomic site. The substrate is simulated by nine carbon atoms. A CO molecule is placed normal to the surface. The binding energy of the adsorption with the C atom closest to the surface is ∼1.7 times that of the adsorption with the O atom closest. By adsorption, a split-off state is formed far below the valence band. Its wave function consists of the bonding combination of the atomic orbitals of the C and O atom (the 2 p orbital of C is only slightly involved) and of the substrate atoms that are nearest and next-nearest to the C atom. The formation of this state is largely responsible for the CO-diamond bond. The overlap-population analysis shows that the bond is well localized.