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Updated: Apr 16, 2026
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Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package
Published on: September 17, 2021
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Exploring composition fluctuations and their dynamics in binary mixtures using coarse-grained molecular dynamics
Siddharth Sundararaman1,2, Suman Chakraborty2, G Brian Stephenson3
1Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, USA.
The Journal of Chemical Physics
|April 15, 2026
Summary
Molecular simulations reveal critical fluctuations in rare earth element extractant mixtures. These findings help predict liquid-liquid extraction phase behavior and improve separation processes.
Area of Science:
- Chemical Engineering
- Materials Science
- Computational Chemistry
Background:
- Liquid-liquid extraction is crucial for separating rare earth elements and strategic materials.
- Phase instabilities and third-phase formation limit the efficiency of these processes.
- Molecular simulation of these phase transitions is complex due to emergent long-range structures.
Purpose of the Study:
- To investigate the structure, scattering behavior, and dynamics of amide/diluent systems using molecular simulations.
- To understand the mesoscale structure and dynamics relevant to liquid-liquid extraction phase behavior.
- To establish criteria for achieving converged simulation statistics of critical fluctuations.
Main Methods:
- Coarse-grained molecular dynamics simulations using the MARTINI 2.0 force field.
- Simulations conducted across various extractant mole fractions and temperatures.
- Analysis of scattering profiles, correlation lengths, and dynamical properties.
Main Results:
- Equilibrium composition fluctuations exhibit scattering profiles described by the Ornstein-Zernike form.
- Correlation lengths and intensities show power-law growth consistent with 3D Ising critical exponents.
- Three distinct dynamical processes (diffusive, convective, vibrational) were identified.
Conclusions:
- Simulation results provide a framework for linking mesoscale structure and dynamics to experimental measurements.
- The study quantifies equilibration criteria for critical fluctuations in simulations.
- Findings aid in understanding and optimizing liquid-liquid extraction processes for strategic material separation.
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