A statistical mechanical study of current spikes due to phase transitions at electrode-electrolyte interfaces

摘要

We develop a statistical mechanical description of current spikes experimentally measured during first-order phase transitions on electrode surfaces. We interpret an experimental current spike as an averaged result of the finite-size effects for a large ensemble of crystalline domains (crystals) that are formed on the electrode surface, i.e., as an envelope of mutually shifted single-crystal spikes of various heights and widths. Rather than starting with a particular lattice gas model, we use rigorous results of Borgs and Kotecky on the finite-size effects valid for a large class of models to describe, in a unifying way, a spike corresponding to a first-order phase transition in a single crystal. We apply our results to fit theoretical spikes to experiment with very good precision. Whenever a phase transition is microscopically simulated by a lattice gas model, the data taken from experiment can be used to determine the strength of interactions in the model. As an illustration, we consider two experimental processes, both of which we model with the standard one-component lattice gas.