Charging and stabilization of Pd atoms and clusters on an electron-rich MgO surface

We report density functional theory calculations on the interaction of Pd atoms and small I'd clusters with an electron-rich MgO surface. This surface can be generated by forming a specific kind of defects, named (H+)(e(-)) centers, using well known chemical recipes. By deposition of gas-phase I'd atoms on the properly functionalized MgO surface, one can generate collections of small Pd cluster anions with peculiar chemical properties. The (H+)(e(-)) centers act as nucleation sites for diffusing Pd atoms and favor the formation of small, thermally stable Pd. clusters. The presence of an extra charge on the metal cluster results in a large vibrational red-shift of adsorbed CO molecules. The present results intend to stimulate experimental work to produce stable metal cluster anions on the surface of an ionic oxide. (C) 2008 Elsevier B.V. All rights reserved.