Abstract

The interaction of transition metals belonging to the group Pt-Pd-Ni and the period Ni-Cu-Zn, with an Fs center of the MgO (100) surface was investigated using density functional theory. This study was aimed at finding the effect of the electron delocalization of an MgO oxygen vacancy on the interaction energies of the metals with the defect and the electronic configuration of the adsorbed metal atom. The degree of electron delocalization was determined from the maximum values of the electron localization function (ELF). It is confirmed that there are two electrons largely localized in the center of the Fs vacancy. These electrons can delocalize over an adsorbed metal atom. This is the reason for the stabilization of some surface complexes. The MO analysis shows that the filling and the symmetry of the last occupied orbitals of the complex M- Fs/MgO depends on the kind of metal. In the case of Ni and Pt the orbitals from HOMO until HOMO-4 are d orbitals and the interaction orbital is the HOMO-5, while for Pd the interaction orbital is the HOMO and the orbitals HOMO-1 until HOMO-5 are d character. This information is very useful for the study of the interaction of a hydrogen atom with del metal- Fs/MgO complex. The oxygen vacancy modifies the interaction of a hydrogen atom with a metal deposited on the defect site due to changes in the electronic configuration of the metal. Therefore, the chemical activity of the metal strongly depends on the interaction metal support. © 2006 The American Physical Society.