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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Simulating critical dynamics in liquid mixtures: short-range and long-range contributions
Subir K Das1, Jan V Sengers, Michael E Fisher
1Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA.
The Journal of Chemical Physics
|October 16, 2007
Summary
Computer simulations of critical dynamics in binary mixtures align with Stokes-Einstein predictions for decay rates. This study confirms that simulation methods accurately capture background contributions to diffusion coefficients, validating their use for dynamic critical behavior research.
Area of Science:
- Physical Chemistry
- Computational Physics
- Materials Science
Background:
- Critical dynamics near phase transitions exhibit unique behaviors.
- The Stokes-Einstein relation describes diffusion in systems near equilibrium.
- Previous work by Das et al. showed consistency with Stokes-Einstein for decay rates.
Purpose of the Study:
- To validate molecular dynamics simulations for studying dynamic critical behavior.
- To investigate noncritical contributions to the diffusion coefficient in binary mixtures.
- To further confirm the applicability of Stokes-Einstein predictions in simulated critical systems.
Main Methods:
- Molecular dynamics simulations of a binary Lennard-Jones mixture.
- Analysis of order-parameter fluctuations near criticality.
- Calculation of diffusion coefficients and their background contributions.
Main Results:
- Simulation results for the asymptotic decay rate of order-parameter fluctuations are consistent with Stokes-Einstein behavior.
- Noncritical contributions to the computed diffusion coefficient agree with theoretical and experimental data.
- The study reinforces the validity of using simulations to study dynamic critical phenomena.
Conclusions:
- Molecular dynamics simulations are a feasible tool for investigating dynamic critical behavior.
- The agreement between simulations, theory, and experiment strengthens the understanding of critical phenomena in binary mixtures.
- This research validates computational approaches for predicting transport properties near critical points.
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