Model for the Solid-Liquid Interfacial Free Energy at High Pressures

Area of Science:

• Materials Science
• Physical Chemistry
• Thermodynamics

Background:

• Interfacial free energy is crucial for modeling solidification kinetics via classical nucleation theory (CNT).
• Existing models often rely on equilibrium or near-ambient pressure assumptions, limiting their applicability.
• Non-equilibrium conditions, like high pressures in dynamic-compression experiments, necessitate advanced modeling approaches.

Purpose of the Study:

• To derive a robust solid-liquid interfacial free-energy model for high-pressure, non-equilibrium conditions.
• To incorporate atom-pair interaction enthalpies and interface roughness using the Temkin n-layer model.
• To validate the model's applicability to diverse materials, specifically water and gallium.

Main Methods:

• Developed a new interfacial free-energy model considering interaction enthalpies and multilayer interface disorder.
• Applied the Temkin n-layer model to account for interface roughness.
• Integrated the model into CNT-based simulations for solidification kinetics.

Main Results:

• The derived model successfully predicts solidification kinetics under high-pressure dynamic-compression conditions.
• Simulations for water solidifying to ice VII showed good agreement with experimental data.
• The model demonstrates applicability to various materials with minimal empirical fitting.

Conclusions:

• The new interfacial free-energy model overcomes limitations of equilibrium-based approaches.
• It provides accurate predictions for non-equilibrium solidification phenomena.
• This work enhances the predictive power of CNT for materials under extreme conditions.