Communication: Thermodynamics of condensed matter with strong pressure-energy correlations

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Abstract

We show that for any liquid or solid with strong correlation between its NVT virial and potential-energy equilibrium fluctuations, the temperature is a product of a function of excess entropy per particle and a function of density, T = f(s)h(ρ). This implies that (1) the system's isomorphs (curves in the phase diagram of invariant structure and dynamics) are described by h(ρ)/T = Const., (2) the density-scaling exponent is a function of density only, and (3) a Grüneisen-type equation of state applies for the configurational degrees of freedom. For strongly correlating atomic systems one has h(ρ) = ∑nCnρn/3 in which the only non-zero terms are those appearing in the pair potential expanded as v(r) = ∑nvnr−n. Molecular dynamics simulations of Lennard-Jones type systems confirm the theory.
OriginalsprogEngelsk
TidsskriftJournal of Chemical Physics
Vol/bind136
Udgave nummer6
Sider (fra-til)061102-1 - 061102-4
Antal sider4
ISSN0021-9606
DOI
StatusUdgivet - 2012

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