Falsifiability Test for Classical Nucleation Theory.

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Physics

Background:

• Classical nucleation theory (CNT) relies on the capillarity approximation, linking nucleation to bulk properties.
• Experimental and simulation data frequently deviate from CNT predictions, prompting theoretical extensions.
• The validity of CNT and its approximations remains an active area of scientific debate.

Purpose of the Study:

• To devise a falsifiability test for nucleation theories based on the capillarity approximation.
• To investigate scenarios where nucleation theories predict identical rates for different crystal polymorphs.
• To challenge the core assumptions of CNT by examining systems with identical free energies across polymorphs.

Main Methods:

• Developed a falsifiability test for capillarity-based nucleation theories.
• Designed a model system where all crystal polymorphs share identical bulk and interfacial free energies.
• Conducted extensive molecular simulations to observe nucleation behavior in the designed system.

Main Results:

• Molecular simulations demonstrated significantly different nucleation properties among polymorphs.
• These simulation results directly contradicted the predictions of classical nucleation theory.
• The observed discrepancies were attributed to the neglect of liquid phase structural fluctuations in CNT.

Conclusions:

• CNT's capillarity approximation is insufficient for accurately predicting nucleation behavior, especially concerning polymorph differentiation.
• The theory's limitation stems from its failure to account for dynamic structural fluctuations in the liquid phase.
• This study provides a critical test for nucleation theories and highlights the importance of dynamic liquid properties in crystallization processes.