Chemical potential evaluation in NVT lattice-gas simulations

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Statistical Mechanics

Background:

• Calculating chemical potential in lattice-gas models is crucial for understanding phase behavior.
• Traditional methods like Widom insertion/deletion require extensive sampling.
• Periodic boundary conditions in simulations introduce complexities for interaction calculations.

Purpose of the Study:

• To develop an efficient and accurate method for evaluating the chemical potential of periodic lattice-gas systems.
• To leverage the discrete nature of the partition function for improved computational strategy.
• To compare simulation results with theoretical predictions.

Main Methods:

• Utilizing the small system grand ensemble approach.
• Treating a sublattice (small system) and its complement (reservoir sublattice) as separate subsystems.
• Optionally restoring boundary connections between reservoir sublattice sites and the small system to enhance accuracy.

Main Results:

• The proposed method efficiently calculates chemical potential without additional sampling.
• Demonstrated accuracy by comparing simulation results (μVT) with canonical ensemble (NVT) simulations.
• The technique is applicable to lattice-gas systems with arbitrarily ranged interactions.

Conclusions:

• The small system grand ensemble offers an efficient alternative for chemical potential calculations in lattice-gas models.
• The method provides accurate results and can be improved by addressing boundary effects.
• This approach simplifies the simulation of complex interacting systems.