A Two-parameter Extension of Classical Nucleation Theory

TL;DR

This paper introduces a two-parameter stochastic model for diffusion-limited nucleation, extending classical theory, and demonstrates improved accuracy in predicting nucleation rates and pathways, especially for protein solutions.

Contribution

The paper develops a two-variable stochastic model based on fluctuating hydrodynamics, generalizing classical nucleation theory and providing more accurate predictions.

Findings

The model aligns well with numerical simulations.

Classical theory underestimates critical cluster formation time.

The discrepancy is due to complex dynamics, not free energy errors.

Abstract

A two-variable stochastic model for diffusion-limited nucleation is developed using a formalism derived from fluctuating hydrodynamics. The model is a direct generalization of the standard Classical Nucleation Theory. The nucleation rate and pathway are calculated in the weak-noise approximation and are shown to be in good agreement with direct numerical simulations for the weak-solution/strong-solution transition in globular proteins. We find that Classical Nucleation Theory underestimates the time needed for the formation of a critical cluster by two orders of magnitude and that this discrepancy is due to the more complex dynamics of the two variable model and not, as often is assumed, a result of errors in the estimation of the free energy barrier.