Excess entropy of strongly coupled Yukawa fluids

TL;DR

This paper investigates the excess entropy of strongly coupled Yukawa fluids, proposing new estimates, scaling relations, and analyzing the Frenkel line, with implications for complex plasma and colloidal systems.

Contribution

It introduces a vibrational approach for entropy estimation, explores the quasiuniversal freezing entropy, and refines the entropy scaling and phase diagram analysis for Yukawa fluids.

Findings

Vibrational paradigm accurately estimates entropy without adjustable parameters.

Weak dependence of freezing entropy on screening parameter explained by linear function.

Modified Rosenfeld-Tarazona scaling relates excess entropy to transport properties.

Abstract

The entropy of strongly coupled Yukawa fluids is discussed from several perspectives. First, it is demonstrated that a vibrational paradigm of atomic dynamics in dense fluids can be used to obtain a simple and accurate estimate of the entropy without any adjustable parameters. Second, it is explained why a quasiuniversal value of the excess entropy of simple fluids at the freezing point should be expected, and it is demonstrated that a remaining very weak dependence of the freezing point entropy on the screening parameter in the Yukawa fluid can be described by a simple linear function. Third, a scaling of the excess entropy with the freezing temperature is examined, a modified form of the Rosenfeld-Tarazona scaling is put forward, and some consequences are briefly discussed. Fourth, the location of the Frenkel line on the phase diagram of Yukawa systems is discussed in terms of the excess entropy and compared with some predictions made in the literature. Fifth, the excess entropy scaling of the transport coefficients (self-diffusion, viscosity, and thermal conductivity) is reexamined using the contemporary datasets for the transport properties of Yukawa fluids. The results could be of particular interest in the context of complex (dusty) plasmas, colloidal suspensions, electrolytes, and other related systems with soft pairwise interactions.