Abstract

QUINTANAR, C; CABALLERO, R; ULISES REVELES, J  and  KHANNA, S.N.. Nature of the bonding, surface relaxation and charge transfer of Au dimmers on an MgO(100) surface. Rev. mex. fis. [online]. 2012, vol.58, n.1, pp.77-85. ISSN 0035-001X.

First principles electronic structure investigations of the nature of adsorption, relaxation of the atoms near the adsorption site, and the charging of the Au₂ particle on the relaxed-rumpled MgO(100) surface have been carried out within the density functional theory-cluster-embedding approach. The investigations focus on an Au₂ molecule, perpendicular to the surface, adsorbed at different locations. Three bonding sites are studied: a five coordinated oxygen regular terrace site O_5c, an F_s neutral color center (two electrons in an O vacancy), and an F⁺_s positive charged color center (one electron in an O vacancy). The studies indicate that large relaxation of the neighboring atoms and large charge transfer occurs for an Au₂ over the color centers. An analysis of the one-electron energy levels of the Au dimer, the MgO surface and the Au₂MgO(100) complex for each absorption site allows us to rationalize the nature of the bonding, surface relaxation, calculated absorption and dimerization energies and electron charge transfers.

Keywords : Supported gold nanoparticles; gold catalysis; density functional theory; metal oxides.