Underpotential versus overpotential deposition: a first-principles calculation

In this work we take the first steps towards a systematic theoretical study of underpotential deposition (upd) systems involving d metals and compare them with systems that present overpotential deposition (opd). We report pr eliminary results from first-principles calculations based on density funct ional theory for two typical systems: Ag on Au(111)(upd), where the lattice mismatch is practically negligible, and Cu on Ag(111)(opd). Comparative ca lculations were made for Au adsorption on Ag(111), with the prediction of u pd for this system. (C) 1998 Elsevier Science S.A. All rights reserved.