Perspective: Excessentropy scaling
Abstract
This article gives an overview of excessentropy scaling, the 1977 discovery by Rosenfeld that entropy determines properties of liquids like viscosity, diffusion constant, and heat conductivity. We give examples from computer simulations confirming this intriguing connection between dynamics and thermodynamics, counterexamples, and experimental validations. Recent uses in applicationrelated contexts are reviewed, and theories proposed for the origin of excessentropy scaling are briefly summarized. It is shown that if two thermodynamic state points of a liquid have the same microscopic dynamics, they must have the same excess entropy. In this case, the potentialenergy function exhibits a symmetry termed hidden scale invariance, stating that the ordering of the potential energies of configurations is maintained if these are scaled uniformly to a different density. This property leads to the isomorph theory, which provides a general framework for excessentropy scaling and illuminates, in particular, why this does not apply rigorously and universally. It remains an open question whether all aspects of excessentropy scaling and related regularities reflect hidden scale invariance in one form or other.
 Publication:

Journal of Chemical Physics
 Pub Date:
 December 2018
 DOI:
 10.1063/1.5055064
 Bibcode:
 2018JChPh.149u0901D