On the system size dependence of the diffusion coefficients in MD simulations: A simple correction formula for pure dense fluids

Sergey Khrapak

doi:10.1021/acs.jpcb.3c07184

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arXiv · 2402.09348

On the system size dependence of the diffusion coefficients in MD simulations: A simple correction formula for pure dense fluids

Sergey Khrapak

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Abstract

A practical correction formula relating the self-diffusion coefficient of dense liquids from molecular dynamics simulations with periodic boundary conditions to the self-diffusion coefficient in the thermodynamic limit is discussed. This formula applies to pure dense fluids and has a very simple form $D=D_0(1-\gamma N^{-1/3})$, where $D_0$ is the self-diffusion coefficient in the thermodynamic limit and $N$ is the number of particles in the simulation. The numerical factor $\gamma$ depends on the geometry of the simulation cell. Remarkably, $\gamma\simeq 1.0$ for the most popular cubic geometry. The success of this formula is supported by results from MD simulations, including very recent simulations with a ``magic'' simulation geometry.

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Sergey Khrapak. 2024-02-14. On the system size dependence of the diffusion coefficients in MD simulations: A simple correction formula for pure dense fluids. https://doi.org/10.1021/acs.jpcb.3c07184

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