Underpotential Deposition of Cu on Au(111): Implications of the HB Model

摘要

In recent papers a model for the underpotential deposition of Cu on Au(111) inthe presence of bisulfate ions was proposed. In this model it was assumed that the bisulfate ions formed a square root of 3 times square root of 3 template. This template leaves a honeycomb lattice of free sites for the adsorption of copper. The clear implication is that the first peak has 2/3 of a monolayer of Cu. The second peak corresponds to the replacement of the bisulfate by copper in the adlayer. We showed also that the broad foot of the first peak is due to a second order hard hexagon like transition, which is seen experimentally by Itaya and Kolb. The interpretation, based on the STM and LEED observations, that the first peak corresponds to only 1/3 of a monolayer, is consistent with our model if it is the bisulfate ion that is actually seen in those experiments.