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Simplistic Coulomb forces in molecular dynamics: comparing the Wolf and shifted-force approximations
J S Hansen1, Thomas B Schrøder, Jeppe C Dyre
1DNRF Centre "Glass and Time", IMFUFA, Department of Science, Systems and Models, Roskilde University , Postbox 260, DK-4000 Roskilde, Denmark.
The Journal of Physical Chemistry. B
|April 14, 2012
Summary
The shifted forces (SF) method accurately simulates bulk systems with Coulomb forces, matching the Wolf method
Area of Science:
- Computational physics
- Materials science
- Chemical physics
Background:
- Accurate simulation of bulk systems with Coulomb forces is crucial in computational physics and materials science.
- The Wolf method and Ewald summation are commonly used for these simulations, but can be computationally intensive.
- The shifted forces (SF) method offers a potential alternative for efficient calculations.
Purpose of the Study:
- To compare the accuracy and efficiency of the Wolf method and the shifted forces (SF) method for simulating bulk systems with Coulomb forces.
- To evaluate the performance of the SF method against established Ewald summation and particle mesh Ewald methods.
- To determine the optimal parameters for the Wolf method and assess convergence criteria.
Main Methods:
- Comparison of the Wolf method and the shifted forces (SF) method using Hansen-McDonald molten salt and SPC/Fw liquid water models.
- Validation against Ewald summation and particle mesh Ewald methods as benchmarks for true behavior.
- Analysis of structural and dynamical properties, potential energy, and radial distribution functions.
Main Results:
- The SF method reproduces structural and dynamical properties as accurately as the Wolf method for the Hansen-McDonald molten salt model.
- Optimal Wolf damping parameters are property-dependent, and potential energy/radial distribution functions are poor convergence indicators.
- The SF method shows good agreement with Wolf and particle mesh Ewald methods for liquid water, confirming previous findings.
Conclusions:
- The shifted forces (SF) method provides an accurate and computationally efficient alternative to the Wolf method for simulating bulk systems with Coulomb forces.
- The SF method offers a speed-up of 2-3 times compared to the Wolf method.
- The simpler and faster SF method can replace the Wolf method when accurate results are achieved, particularly for the studied systems.
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