An analysis of adsorbate mobility from the kinetics of two-dimensional domain growth: precursor-mediated surface diffusion

We have conducted a Monte Carlo investigation of the relationship between the rate of domain growth in a quenched, chemisorbed overlayer and the rate of adatom hopping. We propose an analysis of domain growth kinetics which accounts for the non-equilibrium diffusion in these systems and yields the complete, time-dependent proportionality factor for growth in the Monte Carlo model. Similar analyses applied to analogous experimental systems could yield a very detailed description of the non-equilibrium adsorbate mobility. We find that, even when the proportionality factor for domain growth can be known exactly, an Arrhenius plot of this quantity does not yield the most probable microscopic diffusion barrier. This occurs because adsorbate lateral interactions dictate that the overall rate is actually a distribution of rates and affirms the conclusions of previous studies, which have shown the limitations of the Arrhenius analysis for systems with multiple activation barriers.