Solvent fluctuations in the solvation shell determine the activation barrier for crystal growth rates

Significance Solution crystallization is a widely used technique to grow crystalline materials such as pharmaceuticals, agrochemicals, catalysts, semiconductors, and metal–organic frameworks. The highly probabilistic nature and complex molecular processes spanning multiple lengths and time scales have prevented full mechanistic understanding of crystallization processes for over a century. Here we show fluctuations in the solvation shell are key molecular events that explain and unify the empirical observations laid down since the inception of crystallization research. The activation barrier of the growth processes obtained from these molecular fluctuations can be used to estimate growth rates that show reasonable agreement with the experimental observations, hinting at the rise of additional and efficient strategies to control solution crystallization.