Theoretical Analysis of the Structure, Thermodynamics, and Shear Elasticity of Deeply Metastable Hard Sphere Fluids

TL;DR

This paper uses advanced theoretical methods to analyze the structure, thermodynamics, and shear elasticity of deeply metastable hard sphere fluids, revealing new behaviors and connections consistent with experimental and simulation data.

Contribution

It applies a novel combination of microscopic equilibrium liquid state theory and mode coupling theory to explore deeply metastable regimes, uncovering new structural and thermodynamic phenomena.

Findings

Predicted divergent inverse power laws for pair correlation functions and pressure.

Identified two distinct exponential growth regimes in shear elastic modulus.

Discovered connections between density fluctuations, compressibility, structure, and elasticity.

Abstract

The structure, thermodynamics and slow activated dynamics of the equilibrated metastable regime of glass-forming fluids remains a poorly understood problem of high theoretical and experimental interest. We apply a highly accurate microscopic equilibrium liquid state integral equation theory that has not been previously explored in the deeply metastable regime, in conjunction with na\"ive mode coupling theory of particle localization, to study in a unified manner the structural correlations, thermodynamic properties, and dynamic elastic shear modulus in deeply metastable hard sphere fluids. New and distinctive behaviors are predicted including divergent inverse critical power laws for the contact value of the pair correlation function, pressure, and inverse dimensionless compressibility, and a splitting of the second peak and large suppression of interstitial configurations of the pair correlation function. The dynamic elastic modulus is predicted to exhibit two distinct exponential growth regimes with packing fraction that have strongly different slopes. These new thermodynamic, structural, and elastic modulus results are consistent with simulations and experiments. Perhaps most unexpectedly, connections between the amplitude of long wavelength density fluctuations, dimensionless compressibility, local structure, and the dynamic elastic shear modulus are discovered. These connections are more broadly relevant to understand the slow activated relaxation and mechanical response of colloidal suspensions in the ultra-dense metastable region and deeply supercooled thermal liquids in equilibrium.