Phase Equilibria Modeling with Systematically Coarse-Grained Models-A Comparative Study on State Point...

Area of Science:

• Soft matter physics
• Computational chemistry
• Thermodynamics

Background:

• Coarse-grained (CG) models simplify complex molecular systems for simulations.
• Parameterization methods critically influence the accuracy of CG models.
• Reproducing vapor-liquid equilibrium (VLE) is crucial for soft matter applications.

Purpose of the Study:

• To compare the effectiveness of different CG model parameterization methods.
• To evaluate the ability of CG models to reproduce VLE thermodynamics.
• To assess the transferability of interaction potentials across different state points.

Main Methods:

• Developed CG models using structure-based and coupling free energy-based methods.
• Utilized reference fine-grained simulations for parameterization.
• Calculated VLE properties and liquid structure for hexane and perfluorohexane.

Main Results:

• Structure-based CG models overestimated pressure, performing poorly in VLE reproduction.
• Coupling free energy methods, particularly conditional reversible work, accurately reproduced the VLE phase diagram.
• CG models parameterized at 300 K showed accurate thermodynamic property prediction up to the critical point.

Conclusions:

• Parameterization based on coupling free energies yields superior VLE thermodynamics reproduction compared to structure-based methods.
• The conditional reversible work method demonstrates excellent state point transferability for CG models.
• Accurate VLE prediction and transferability are achievable with appropriate CG model parameterization strategies.