Title: Critical and supercritical properties of Lennard–Jones fluids
Abstract: Critical properties for Lennard–Jones fluids are seen to be consistent with an alternative description of liquid–gas criticality to the van der Waals hypothesis. At the critical temperature (Tc) there is a critical dividing line on the Gibbs density surface rather than a critical point singularity. We report high-precision thermodynamic pressures from MD simulations for more than 2000 state points along 7 near-critical isotherms, for system sizes N = 4096 and 10,976 for a Lennard–Jones fluid. We obtain kBTc/ɛ = 1.3365 ± 0.0005 and critical pressure pcσ3/ɛ = 0.1405 ± 0.0002 which remains constant between two coexisting densities ρc(gas) σ3 = 0.266 ± 0.01 and ρc(liquid) σ3 = 0.376 ± 0.01 determined by supercritical percolation transition loci. A revised plot of the liquid–vapor surface tension shows that it goes to zero at this density difference, which, along with a direct evaluation of Gibbs chemical potential along the critical isotherm, reaffirms a coexisting dividing line of critical states. Analysis of the distribution of clusters from MD simulations along a supercritical isotherm (T* = 1.5) gives new insight into the supercritical boundaries of gas and liquid phases, and the nature of the supercritical mesophase.
Publication Year: 2013
Publication Date: 2013-08-07
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 34
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