Can experiments select the configurational component of excess entropy?

TL;DR

This paper presents an experimental approach to distinguish vibrational and configurational components of excess entropy in liquids, analyzing various measurements of glass formers to quantify their contributions.

Contribution

It introduces a novel experimental method to separate vibrational and configurational excess entropy components in liquids.

Findings

Approximately 70% of excess entropy is configurational in the studied glass formers.

The method combines dynamic and thermodynamic measurements across temperature and pressure.

Results support the significant role of configurational entropy in glass-forming liquids.

Abstract

We introduce an experimental method of assessing the vibrational and configurational components of the excess entropy of a liquid over crystal, based on a joined investigation of dynamic and thermodynamic properties as a function of temperature and pressure. We analyze light scattering, dielectric, calorimetric and dilatometric measurements of three prototype glass formers, orthoterphenyl, salol, and glycerol. In all cases we find that about 70% of the excess entropy is configurational in nature.