Consequences of minimising pair correlations in fluids for dynamics, thermodynamics and structure

• Published in: Molecular physics Vol. 114; no. 16-17; pp. 2411 - 2423
• Main Authors: Jadrich, R. B., Lindquist, B. A., Bollinger, J. A., Truskett, T. M.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01.09.2016; Taylor & Francis Ltd
• Subjects: Computational fluid dynamics; Correlation; Density; density fluctuations; Disorders; Dynamics; Entropy; Fluctuation; Fluids; Hyperuniformity; liquid structure; pair correlations
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268976.2016.1159742

Liquid-state theory, computer simulation and numerical optimisation are used to investigate the extent to which positional correlations of a hard-sphere fluid - as characterised by the radial distribution function and the two-particle excess entropy - can be suppressed via the introduction of auxiliary pair interactions. The corresponding effects of such interactions on total excess entropy, density fluctuations and single-particle dynamics are explored. Iso-g processes, whereby hard-sphere-fluid pair structure at a given density is preserved at higher densities via the introduction of a density-dependent, soft repulsive contribution to the pair potential, are considered. Such processes eventually terminate at a singular density, resulting in a state that - while incompressible and hyperuniform - remains unjammed and exhibits fluid-like dynamic properties. The extent to which static pair correlations can be suppressed to maximise pair disorder in a fluid with hard cores, determined via direct functional maximisation of two-body excess entropy, is also considered. Systems approaching a state of maximised two-body entropy display a progressively growing bandwidth of suppressed density fluctuations, pointing to a relation between 'stealthiness' and maximal pair disorder in materials.