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Geometric integrator for simulations in the canonical ensemble.
Diego Tapias1, David P Sanders1, Alessandro Bravetti2
1Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México 04510, Mexico.
The Journal of Chemical Physics
|September 3, 2016
Summary
We developed a novel geometric integrator for molecular dynamics simulations. This method accurately preserves the invariant distribution, ensuring correct ensemble sampling for various thermostats in physical systems.
Area of Science:
- Computational Physics
- Physical Chemistry
- Statistical Mechanics
Background:
- Molecular dynamics simulations are crucial for understanding physical systems.
- Accurate sampling of the canonical ensemble is essential for reliable thermodynamic results.
- Existing integrators can introduce drift, compromising ensemble accuracy.
Purpose of the Study:
- To introduce a novel geometric integrator for molecular dynamics simulations.
- To preserve the invariant distribution in the canonical ensemble for density dynamics.
- To provide a unified framework for studying thermostat effects.
Main Methods:
- Developed a geometric integrator preserving invariant distribution.
- Implemented a second-order, time-reversible method.
- Applied to Lennard-Jones system simulations with three thermostats.
Main Results:
- The geometric integrator demonstrated good conservation of geometrical properties.
- Expected thermodynamic results were accurately recovered.
- Compared to the Gear integrator, our method showed no drift in the invariant quantity.
Conclusions:
- The proposed geometric integrator effectively samples the correct ensemble.
- This unified framework facilitates the study of different thermostats and their impact.
- The integrator offers an advantage over non-geometric methods for canonical ensemble simulations.
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