Monte Carlo Simulations of the Underpotential Deposition of Metal Layers on Metallic Substrates: Phase Transitions and Critical Phenomena.

M. CECILIA GIMENEZ; EZEQUIEL P. M. LEIVA; EZEQUIEL ALBANO

Modern Aspects of Electrochemistry

Springer

Año: 2008;

The adsorption of a metal monolayer or submonolayer for thesystems Ag/Au(100), Au/Ag(100), Ag/Pt(100), Pt/Ag(100), Au/Pt(100),Pt/Au(100), Au/Pd(100) and Pd/Au(100) was studied by means of lattice Monte Carlo simulations.It was found that for some systems, the adsorbate atoms successively occupy kink sites,  step sites and the complete monolayer.On the other hand, for other systems, we observe 2-D alloys between substrate and adsorbate-type atoms.In particular, based on the fact that the underpotential deposition  of Ag atoms on the Au(100) surface exhibits sharp first-order phase transition at well defined values of  the coexistence  chemical potential, we have also performed  extensive simulations aimed to investigate the hyteretic  dynamic behavior of the system close to coexistence upon the application of a  periodic signal.