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Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package

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Explicit Configurational Entropy of Mixing in Molecular Dynamics Simulations.

T Hanke¹, A L Upterworth¹, D Sebastiani¹

¹Department of Chemistry, Martin Luther University, 06120 Halle, Germany.

The Journal of Physical Chemistry Letters

|November 5, 2024

Summary

This summary is machine-generated.

Calculating mixing entropy in nonequilibrium systems is challenging. This study introduces a new method using particle coordinates for real-time analysis of mixing and demixing processes in molecular simulations.

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Area of Science:

Statistical Mechanics
Computational Chemistry
Materials Science

Background:

The equilibrium entropy of mixing is well-defined by molar fractions.
Calculating intermediate mixing entropy for transient, nonequilibrium states from particle coordinates has been a significant challenge.
Existing methods often require computationally intensive or indirect approaches.

Purpose of the Study:

To develop a direct and computationally efficient method for calculating the configurational entropy of mixing for nonequilibrium states.
To enable on-the-fly determination of the degree of mixing during molecular dynamics simulations.
To provide a tool for analyzing the dynamics of mixing and demixing processes.

Main Methods:

A novel, simple expression for configurational entropy of mixing was derived.
The method relies solely on the instantaneous particle coordinates.
The approach was validated using molecular dynamics simulations of various mixtures.

Main Results:

The proposed method successfully calculates the configurational entropy of mixing from instantaneous particle coordinates.
The scheme allows for real-time monitoring of mixing and demixing dynamics.
Applicability demonstrated across systems with varying mixing and demixing rates.

Conclusions:

The new method offers a direct and efficient way to quantify mixing in nonequilibrium systems.
This approach facilitates the study of dynamic mixing processes in molecular simulations.
The findings provide valuable insights into the kinetics of mixing and phase behavior.