Dual-potential approach for coarse-grained implicit solvent models with accurate, internally consistent energetics...

Area of Science:

• Computational chemistry
• Statistical mechanics
• Materials science

Background:

• Coarse-grained (CG) models simplify complex molecular systems.
• Accurately capturing temperature-dependent properties in CG models remains a challenge.
• Implicit solvent models are crucial for simulating systems with significant solvent entropy.

Purpose of the Study:

• To investigate the dual-potential approach for implicit solvent CG models.
• To assess the accuracy of predicting temperature-dependence of effective CG potentials.
• To establish a link between atomic specific heat and CG energetic fluctuations.

Main Methods:

• Constructing implicit solvent CG models at varying resolutions (R = 0.10–0.95) from Lennard-Jones fluids.
• Employing the dual-potential approach in constant volume and pressure ensembles.
• Approximating many-body potentials using pair and volume potentials derived from multiscale coarse-graining and self-consistent pressure-matching.

Main Results:

• Pair potentials became more attractive, while volume potentials became more repulsive with increasing temperature.
• The dual-potential approach accurately reproduced atomic energetics and their temperature-dependence.
• An exact relationship between atomic specific heat and CG energetic fluctuations was derived and validated.

Conclusions:

• The dual-potential approach effectively models temperature-dependent properties of implicit solvent CG models.
• This method accurately predicts the thermodynamic specific heat of the underlying atomic system.
• The derived generalized fluctuation relationship enhances the predictive power of CG models.