Pressure calculation in hybrid particle-field simulations.

Area of Science:

• Computational chemistry
• Statistical mechanics
• Materials science

Background:

• Hybrid particle-field simulation techniques combine molecular dynamics (MD) and self-consistent field (SCF) theory.
• Accurate calculation of pressure and stress is crucial for understanding material properties and behavior.

Purpose of the Study:

• To develop a general formulation for calculating instantaneous pressure and stress tensor within hybrid particle-field simulations.
• To implement and validate this formulation for hybrid molecular dynamics-self-consistent field (MD-SCF) simulations.

Main Methods:

• Derivation of pressure and stress tensor expressions from statistical mechanics and SCF free energy functional.
• Implementation of the formulation for MD-SCF simulations.
• Comparison of results with standard MD simulations using pair potentials.

Main Results:

• A general formulation for instantaneous pressure and stress tensor in hybrid MD-SCF simulations was successfully developed.
• The implementation demonstrated suitability for hybrid simulations.
• Calculated pressures showed good agreement with standard MD simulations on model systems.

Conclusions:

• The developed formulation provides a reliable method for calculating pressure and stress in hybrid particle-field simulations.
• This advancement enhances the capability of MD-SCF methods for accurate thermodynamic property evaluation.
• The approach offers a valuable tool for studying complex systems where both particle and field descriptions are necessary.