A formula for the profile of voltammogram spikes in the quasistatic regime.
A phase transition occurring at electrode-electrolyte interfaces is reflected in voltammograms (the current versus voltage plots) as a sharp spike. We derive a general formula fitting the profile of the spikes due to the first-order phase transitions that can be microscopically modeled by classical two-dimensional lattice gases. The quasistatic (near equilibrium) regime is required. The profile is especially essential when interpreting generic voltammograms, where two or more close or overlapping spikes usually appear. Simple direct links between the microscopics of a phase transition and the macroscopic properties of the associated spike are explicitly given. We demonstrate our results on the voltammograms for the underpotential deposition of copper on platinum (111) and (100) and on gold (111) and achieve very good agreement with experiment.
Medved'
I
I
Department of Physics, Constantine the Philosopher University, 949 74 Nitra, Slovakia. imedved@ukf.sk