Adsorption of Cu4, Ag4 and Au4 particles on the regular MgO(0Â 0Â 1) surface: A density functional study using embedded cluster models

Cu4, Ag4, and Au4 species adsorbed on the regular MgO(0 0 1) surface are studied using a density functional method and cluster models embedded in an elastic polarizable environment. The structure of the coinage metal tetramers is only slightly distorted by adsorption on the oxide surface compared to the rhombic-planar arrangement in the gas phase. The most stable adsorption complexes of all three systems feature upright metal planar particles with the M4 moiety orthogonal to the surface and two metal atoms attached to surface oxygen anions. Au4 and Cu4 exhibit substantially stronger binding to the surface than Ag4.