Modelling of silver adhesion on MgO(100) surface with defects

We show how surface defects (especially F-s(0) and V-s(0) centres) can play a major role in the adhesion of Ag (at 1:4 and 1:1 coverages) on the MgO(1 00) surface. Our calculations use a periodic (slab) model and an ab initio Hartree-Fock approach with cc posteriori electron correlation corrections. We are able to analyse the interatomic bond populations, effective charges and multipole moments of ions, in combination with the interface binding en ergy and the equilibrium distances. Both surface defects cause strong redis tributions of the electron density which increase the binding energy of met al atoms by more than an order of magnitude. This implies radiation-induced strengthening of metal adhesion on oxide substrates and clarifies defect m echanisms in nucleating film growth. We compare our atomistic predictions w ith those from simpler methods which might be used for complex technologica lly interesting systems. There is good general agreement with the image int eraction model differences arise partly from different treatments of disper sion and partly from subtle but significant charge redistribution in the Ag . Further, a simple Born-Haber analysis of charge transfer is consistent wi th the several cases predicted in the atomistic calculations.