An Efficient Integrator Scheme for Sampling the (Quantum) Isobaric-Isothermal Ensemble in (Path Integral) Molecular...

Area of Science:

• Computational Chemistry and Physics
• Molecular Dynamics Simulations

Background:

• Most chemical and biological experiments require controlled pressure and temperature.
• Accurate atomic-level simulation of the isobaric-isothermal ensemble is crucial for understanding microscopic mechanisms.

Purpose of the Study:

• To propose a unified scheme for sampling coordinate and volume distributions in molecular simulations.
• To enable accurate simulation of classical and quantum isobaric-isothermal processes.

Main Methods:

• Extension of an efficient configuration sampling approach for the canonical ensemble.
• Implementation of a unified 'middle' scheme adaptable to various barostats (e.g., Martyna-Tuckerman-Tobias-Klein, stochastic cell-rescaling) and thermostats (e.g., Langevin).
• Integration into popular molecular simulation packages (DL_POLY, AMBER, GROMACS).

Main Results:

• The 'middle' scheme accurately simulates isobaric-isothermal processes.
• It allows for increased simulation time intervals (5-10x) without additional numerical effort.
• Achieves converged results for thermodynamic properties in molecular dynamics simulations.

Conclusions:

• The unified 'middle' scheme provides an efficient and accurate method for isobaric-isothermal molecular simulations.
• It enhances the capability of simulating complex molecular systems under controlled conditions.
• Applicable to both classical and quantum molecular dynamics, including path integral simulations.