Brick-CFCMC

Brick-CFCMC performs Monte Carlo simulations for phase- and reaction-equilibria calculations, computing excess chemical potentials (μ^ex) via thermodynamic integration and supporting hybrid MC/MD trial moves to improve sampling in complex chemical systems.

Key Features:

• Thermodynamic integration for μ^ex: Implements thermodynamic integration to compute excess chemical potentials by averaging the derivative of potential energy with respect to a scaling factor λ for intermolecular interactions.
• Per-move μ^ex updates: Updates μ^ex estimates after each Monte Carlo trial move and has been validated on sodium chloride in water.
• Hybrid MC/MD trial moves: Executes short Molecular Dynamics trajectories to collectively displace or rotate all molecules as MC trial moves.
• Energy-drift acceptance and adaptivity: Determines acceptance of hybrid moves by evaluating total energy drift and allows dynamic adjustment of MD time step and trajectory length.
• Improved sampling for viscous systems: Enhances sampling efficiency in viscous or highly interacting fluids, exemplified by deep eutectic solvents.

Scientific Applications:

• Phase and reaction equilibria: Calculation of phase- and reaction-equilibrium properties in multi-component chemical systems.
• Solvation and ion interactions: Computation of μ^ex for studies of solvation effects and ion–water interactions, including sodium chloride in water.
• Sampling in challenging environments: Improved configurational sampling for viscous or highly interactive fluids such as deep eutectic solvents.

Methodology:

Combines Monte Carlo sampling with thermodynamic integration of μ^ex (ensemble averages of ∂U/∂λ) and hybrid MC/MD short MD trajectories, with move acceptance based on total energy drift and adaptive MD time step and trajectory length.