A microscopic approach to crystallization: Challenging the classical/non-classical dichotomy.

Area of Science:

• Physical Chemistry
• Materials Science
• Computational Physics

Background:

• Classical nucleation theory (CNT) provides a foundational understanding of phase transitions.
• However, experimental and simulation studies increasingly reveal non-classical crystallization pathways.
• A unified theoretical framework is needed to reconcile these observations.

Purpose of the Study:

• To develop a fundamental, parameter-free framework for studying crystallization.
• To investigate colloidal crystal and droplet nucleation pathways using this framework.
• To assess the applicability of classical nucleation theory to non-classical pathways.

Main Methods:

• Combined classical density functional theory (DFT) and fluctuating hydrodynamics.
• Studied nucleation of droplets and crystalline solids from colloidal solutions.
• Analyzed critical clusters and computed unstable modes.

Main Results:

• Nucleation pathways for droplets and crystals show early similarities, diverging due to rapid ordering in solids.
• Despite non-classical pathways, cluster size consistently acts as the primary order parameter.
• Nucleation rates can be systematically extracted from the developed formalism.

Conclusions:

• The study provides a nuanced perspective on crystal nucleation, bridging classical and non-classical descriptions.
• Classical nucleation theory can offer reasonable predictions for solids even with non-classical pathways.
• The developed framework offers a systematic approach to studying crystallization dynamics.