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Electrostatic interactions in dissipative particle dynamics-Ewald-like formalism, error analysis, and pressure
Rakesh Vaiwala1, Sameer Jadhav1, Rochish Thaokar1
1Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400 076, India.
The Journal of Chemical Physics
|April 8, 2017
Summary
Accurate dissipative particle dynamic (DPD) simulations require optimal Ewald parameters for charged species. This study provides error estimates for electrostatic energy and force, validating them with DPD simulations and offering a simplified pressure calculation.
Area of Science:
- Computational Physics
- Materials Science
- Physical Chemistry
Background:
- Accurate simulation of charged systems in dissipative particle dynamics (DPD) is crucial for understanding material properties.
- Long-range electrostatic interactions in DPD simulations require specialized summation techniques like Ewald methods.
- The performance of these methods depends heavily on parameters such as the Ewald splitting parameter (α), charge smearing length (λ), and real space cutoff (c).
Purpose of the Study:
- To provide accurate error estimates for electrostatic energy and force in DPD simulations with Slater-type charge distributions.
- To validate these error estimates using DPD simulation results.
- To develop a simplified method for calculating electrostatic pressure without complex Fourier transforms.
Main Methods:
- Derivation of Ewald-like formulas for electrostatic energy and force for Slater-type charge densities.
- Analysis of error estimates as a function of Ewald splitting parameter (α), inverse charge smearing length (β=1/λ), and real space cutoff (c).
- Validation of derived formulae through dissipative particle dynamic (DPD) simulations.
- Development and discussion of a simplified electrostatic pressure estimation method based on minimum-image truncation.
Main Results:
- Formulas for error estimates in electrostatic energy and force were derived and validated against DPD simulations.
- The study demonstrates the impact of α, β, and c on simulation accuracy.
- A computationally efficient method for estimating electrostatic pressure was presented and its validity discussed.
Conclusions:
- The optimal choice of Ewald parameters (α, λ, c) is essential for accurate time evolution in DPD simulations of charged species.
- The provided error estimates and simplified pressure calculation offer valuable tools for improving DPD simulations.
- This work facilitates more reliable and efficient simulations of complex charged systems.