Accession Number : ADA260269


Title :   Sequential Deposition of Copper on Solid Gold (111): A Statistical Model


Corporate Author : PUERTO RICO UNIV RIO PIEDRAS DEPT OF PHYSICS


Personal Author(s) : Blum, L ; Huckaby, Dale A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a260269.pdf


Report Date : 15 Jan 1993


Pagination or Media Count : 13


Abstract : Phase transitions occurring during electrode processes have been studied using a model in which the electrode is a planar wall with sticky adsorption sites. This model is used to explain the underpotential deposition (UPD) of copper on gold (111) in the presence of bisulfate ions. The model assumes that the bisulfate ions form a template for the adsorption of the first 2/3 of a monolayer of copper onto a honeycomb lattice. The centers of the hexagons that form the honeycomb are occupied by the bisulfate. In the absence of copper the bisulfate is desorbed as the electrode becomes more negatively charged, and for that reason the template 'melts' when the fraction of occupied sites drops below a certain critical value, which is estimated using the hard hexagon model of Baxter. We assume strong copper-bisulfate coadsorption, so that in the presence of a sufficiently large amount of Cu the template is reconstructed. Our model explains the qualitative features of the voltammogram, and makes definite predictions for the structure that should be observed.


Descriptors :   *SEQUENTIAL ANALYSIS , *DEPOSITION , *COPPER , *GOLD , *STATISTICAL ANALYSIS , IONS , PREDICTIONS , MODELS , INTERACTIONS , LAYERS , PHASE TRANSFORMATIONS , ADSORPTION , SURFACES , DESORPTION , VOLTAMMETRY , SULFATES , VALUE , TRANSITIONS , WALLS , TEMPLATES , DROPS , ELECTRODES , ELECTRODEPOSITION , IONIZATION POTENTIALS , HONEYCOMB STRUCTURES , CURRENTS , CRYSTAL LATTICES , SITES , STRUCTURES , FILMS , VOLTAGE , SOLIDS , PHASE


Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Crystallography
      Electricity and Magnetism


Distribution Statement : APPROVED FOR PUBLIC RELEASE