Chemical potential calculations in non-homogeneous liquids

Area of Science:

• Thermodynamics
• Computational Chemistry
• Fluid Dynamics

Background:

• Calculating chemical potential in dense, non-homogeneous fluids is crucial for confined fluid thermodynamics.
• Existing methods like the Widom insertion method struggle with accuracy and efficiency at high densities.
• A need exists for robust techniques that provide reliable chemical potential estimates in complex fluid systems.

Purpose of the Study:

• To extend a novel, well-tempered metadynamics-enhanced sampling technique to non-homogeneous fluid systems.
• To address the limitations of traditional methods in accurately computing chemical potential at high densities.
• To validate the new method's performance on a confined Lennard-Jones fluid model.

Main Methods:

• Utilizing well-tempered metadynamics to enhance the sampling of insertion energy.
• Adapting a previously developed method for homogeneous fluids to non-homogeneous systems.
• Applying the technique to a confined Lennard-Jones fluid to assess its efficacy.

Main Results:

• The enhanced sampling technique successfully computes chemical potential in dense, non-homogeneous fluids.
• The method demonstrates improved accuracy and efficiency compared to the classic Widom insertion method.
• A systematic error affecting the Widom method in non-homogeneous systems is mitigated.

Conclusions:

• The novel metadynamics-based approach offers a precise and accurate solution for chemical potential calculations in confined fluids.
• This technique overcomes sampling inefficiencies inherent in traditional methods at high densities.
• The study validates the method's robustness for complex thermodynamic studies of non-homogeneous fluids.