Characteristics of Pd adsorption on the MgO(100) surface: Role of oxygen vacancies - art. no. 075417

Using the ab initio full-potential linearized augmented-plane-wave approach , we have studied the role of surface oxygen vacancies on the characteristi cs of palladium deposition on the MgO (100) surface, In agreement with rece nt theoretical evidence, we find that the adsorption energy of a single Pd atom is considerably enhanced by the defects, and that an important electro n transfer from the substrate towards the adsorbed Pd atom occurs. By consi dering three types of palladium deposits-a single atom, a monolayer, and a bilayer-we have analyzed the evolution of the vacancy-induced interface pro perties as a function of the dimensionality of the deposit and we show that the modifications reported for the isolated Pd adatoms are to a large exte nt present also for more extended deposits. However, the electron transfer across the interface remains localized to the close vicinity of the oxygen vacancy, and the stabilization effect of vacancies is particularly strong o n lower-coordinated metal atoms. This indicates that the major vacancy-indu ced modification of the deposit shall be Limited to those metal atoms at th e cluster edges that adsorb directly at the vacancies.