Direct calculation of solid-liquid coexistence points of a binary mixture by thermodynamic integration

Area of Science:

• Thermodynamics
• Physical Chemistry
• Materials Science

Background:

• Determining solid-liquid coexistence in binary mixtures is crucial for understanding phase behavior.
• Existing methods like Gibbs-Duhem integration can be computationally intensive.
• Bridging the gap between liquid and solid phases requires robust simulation techniques.

Purpose of the Study:

• To introduce a novel thermodynamic integration method for directly connecting liquid and solid phases of binary mixtures.
• To accurately predict solid-liquid coexistence points and melting temperatures.
• To validate the new method against established techniques.

Main Methods:

• Simulations were performed in the isothermal-isobaric semigrand canonical ensemble.
• Key parameters held constant include temperature, pressure, total particle number, and component fugacity fractions.
• Thermodynamic integration was used to calculate the chemical-potential difference between phases.

Main Results:

• The method successfully establishes a reversible path between liquid and solid phases.
• It yields the chemical-potential difference, enabling the location of solid-liquid coexistence points.
• Predicted melting temperatures closely match those from Gibbs-Duhem integration for a Lennard-Jones system.

Conclusions:

• The new thermodynamic integration method provides an accurate and efficient way to determine solid-liquid coexistence in binary mixtures.
• This approach simplifies the study of phase transitions in complex systems.
• The method shows promise for broader applications in materials science and physical chemistry.