Pair Potential That Reproduces the Shape of Isochrones in Molecular Liquids

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Abstract

Many liquids have curves (isomorphs) in their phase diagrams along which structure, dynamics, and some thermodynamic quantities are invariant in reduced units. A substantial part of their phase diagrams is thus effectively one dimensional. The shapes of these isomorphs are described by a material-dependent function of density, h(ρ), which for real liquids is well approximated by a power law, ργ. However, in simulations, a power law is not adequate when density changes are large; typical models, such as Lennard-Jones liquids, show that γ(ρ) ≡ d ln h(ρ)/d ln ρ is a decreasing function of density. This article presents results from computer simulations using a new pair potential that diverges at a nonzero distance and can be tuned to give a more realistic shape of γ(ρ). Our results indicate that the finite size of molecules is an important factor to take into account when modeling liquids over a large density range.
OriginalsprogEngelsk
TidsskriftThe Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
Vol/bind120
Udgave nummer32
Sider (fra-til)7970-7974
Antal sider5
ISSN1520-6106
DOI
StatusUdgivet - 2016

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