Special CPM Seminar

Solute precipitate nucleation: theoretical and computational advances

Baron Peters

UCSB

Nucleation is an activated process by which the first stable embryo is born to initiate a phase transition. Experimental and computational studies of nucleation are difficult because, at any moment in time, the critical nuclei are extremely rare, existing only as ephemeral species before the onset of growth. In addition, nucleation often occurs heterogeneously on sites with unknown characteristics. I will discuss our recent work on LaMer burst nucleation, where theoretical considerations suggest that essentially all of the individual nucleation events occur homogeneously. A simple model suggests that the nucleation kinetics can be extracted from particle size distribution data and from the maximum solute concentration during the LaMer burst. These findings suggest a powerful experimental route to the elusive homogeneous nucleation kinetics, and thereby a stronger bridge between theory and experiment. On the simulation front, there are now several rare events methods that can compute the nucleation rates for single component processes like freezing. In contrast, solute precipitate nucleation continues to pose major challenges. I will present a new seeded simulation approach for solute precipitate nucleation along with an analysis of the factors that influence accuracy of the estimated rates.