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Traversing the nucleation-growth landscape through heterogeneous random walks
Kaicheng Zhu1, Haibin Su1,2
1Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong.
Physical Review. E
|July 19, 2023
Summary
This study introduces a new model for nanocrystal nucleation and growth, explaining early-stage dynamics. It reveals transient prenucleation equilibrium and a crossover regime, improving understanding of crystal formation.
Area of Science:
- Materials Science
- Chemical Physics
- Crystallization Dynamics
Background:
- Classical nucleation theory and Lifshitz-Slyozov-Wagner models inadequately explain early nanocrystal formation dynamics.
- Experimental and simulation advancements reveal limitations of existing theoretical frameworks.
Purpose of the Study:
- To develop a novel model for nucleation-growth dynamics of individual nanocrystals.
- To incorporate activation-adsorption-relaxation pathways into the free energy landscape.
- To address limitations of classical models in describing transient phenomena.
Main Methods:
- Monte Carlo simulations based on transition state theory.
- Derivation of a Fokker-Planck formalism from the master equation.
- Modeling nucleation-growth as a heterogeneous random walk on an extended free energy landscape.
Main Results:
- Identified a transient quasiequilibrium in the prenucleation stage.
- Discovered a postnucleation crossover regime where growth exponents converge to classical limits.
- Generalized power laws to account for dimension and scale effects in crystal growth.
Conclusions:
- The new model accurately describes nanocrystal nucleation-growth dynamics, including transient stages.
- The findings provide a more comprehensive understanding of crystal formation processes.
- The generalized power laws offer insights into the growth of larger crystals.
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