Local density dependent potential for compressible mesoparticles.

Area of Science:

• Computational chemistry
• Molecular dynamics
• Statistical mechanics

Background:

• Traditional molecular simulations struggle with strong non-equilibrium conditions.
• Accurately modeling compressibility in coarse-grained models is challenging.
• Existing methods for local density estimation may not be suitable for complex systems.

Purpose of the Study:

• To develop a coarse-grained molecular simulation method.
• To incorporate internal compressibility of mesoparticles.
• To accurately model systems under strong non-equilibrium conditions.

Main Methods:

• Utilizing mesoparticles composed of multiple molecules.
• Implementing an interparticle potential dependent on the local environment.
• Employing three-dimensional Voronoi tessellation for local density definition.
• Fitting a local density-dependent potential to experimental data.

Main Results:

• A novel coarse-grained description for molecular systems was established.
• The internal compressibility of mesoparticles was successfully considered.
• The method accurately reproduced the Hugoniot curve for nitromethane over a wide pressure and density range.
• Voronoi tessellation proved effective for defining local densities.

Conclusions:

• The proposed mesoparticle approach offers a robust framework for simulating non-equilibrium molecular systems.
• Environment-dependent potentials and Voronoi tessellation are key to capturing compressibility effects.
• This methodology advances the simulation of materials under extreme conditions.