Imperial College London
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ProfessorDanieleDini

Faculty of Engineering, Department of Mechanical Engineering

Professor in Tribology
 
 
 
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Contact

 

+44 (0)20 7594 7242d.dini Website

 
 
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Location

 

669City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Heyes:2023:10.1063/5.0177185,
author = {Heyes, DM and Dini, D and Pieprzyk, S and Braka, AC},
doi = {10.1063/5.0177185},
journal = {J Chem Phys},
title = {Harmonic models and molecular dynamics simulations of isomorph behavior of Lennard-Jones fluids: Excess entropy and high temperature limiting behavior.},
url = {http://dx.doi.org/10.1063/5.0177185},
volume = {159},
year = {2023}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Henchman's approximate harmonic model of liquids is extended to predict the thermodynamic behavior along lines of constant excess entropy ("isomorphs") in the liquid and supercritical fluid regimes of the Lennard-Jones (LJ) potential phase diagram. Simple analytic expressions based on harmonic cell models of fluids are derived for the isomorph lines, one accurate version of which only requires as input parameters the average repulsive and attractive parts of the potential energy per particle at a single reference state point on the isomorph. The new harmonic cell routes for generating the isomorph lines are compared with those predicted by the literature molecular dynamics (MD) methods, the small step MD method giving typically the best agreement over a wide density and temperature range. Four routes to calculate the excess entropy in the MD simulations are compared, which includes employing Henchman's formulation, Widom's particle insertion method, thermodynamic integration, and parameterized LJ equations of state. The thermodynamic integration method proves to be the most computationally efficient. The excess entropy is resolved into contributions from the repulsive and attractive parts of the potential. The repulsive and attractive components of the potential energy, excess Helmholtz free energy, and excess entropy along a fluid isomorph are predicted to vary as ∼T-1/2 in the high temperature limit by an extension of classical inverse power potential perturbation theory statistical mechanics, trends that are confirmed by the MD simulations.
AU  - Heyes,DM
AU  - Dini,D
AU  - Pieprzyk,S
AU  - Braka,AC
DO  - 10.1063/5.0177185
PY  - 2023///
TI  - Harmonic models and molecular dynamics simulations of isomorph behavior of Lennard-Jones fluids: Excess entropy and high temperature limiting behavior.
T2  - J Chem Phys
UR  - http://dx.doi.org/10.1063/5.0177185
UR  - https://www.ncbi.nlm.nih.gov/pubmed/38088434
VL  - 159
ER  -
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