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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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Thermal Diffusion in Binary Mixtures: Transient Behavior and Transport Coefficients from Equilibrium and
Sara Bonella1, Mauro Ferrario2, Giovanni Ciccotti3,4,5
1CECAM Centre Européen de Calcul Atomique et Moléculaire, École Polytechnique Fédérale de Lausanne , Batochime, Avenue Forel 2, 1015 Lausanne, Switzerland.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 17, 2017
Summary
This study combines equilibrium and nonequilibrium molecular dynamics to calculate thermal transport coefficients in binary mixtures. The Dynamical Non-Equilibrium Molecular Dynamics approach analyzes transient and steady-state field evolution for accurate transport analysis.
Area of Science:
- Thermodynamics
- Statistical Mechanics
- Computational Physics
Background:
- Understanding thermal transport in mixtures is crucial for many physical processes.
- Phenomenological equations describe macroscopic transport but require accurate coefficients.
- Molecular dynamics offers a route to microscopic insights into transport phenomena.
Purpose of the Study:
- To compute all coefficients in phenomenological thermal transport equations for a binary mixture.
- To investigate the time evolution of density and temperature fields under a thermal gradient.
- To analyze transient and steady-state transport mechanisms using advanced simulation techniques.
Main Methods:
- Combined equilibrium and nonequilibrium molecular dynamics simulations.
- Employed the Dynamical Non-Equilibrium Molecular Dynamics (D-NEMD) approach.
- Applied local time averaging to enhance signal-to-noise ratio for flux estimation.
Main Results:
- Successfully computed the full set of thermal transport coefficients.
- Monitored the microscopic time evolution of density, temperature, mass, and energy fluxes.
- Characterized transient dynamics leading to the steady state.
Conclusions:
- D-NEMD provides a robust method for analyzing thermal transport in binary mixtures.
- The study ensures system stationarity and clarifies transient transport timescales.
- Improved signal clarity was achieved even with limited statistical data.
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