Static and dynamic properties of a binary, symmetric mixture of ultrasoft particles in the vicinity of criticality

TL;DR

This study explores the static and dynamic behaviors of a binary ultrasoft particle mixture near criticality using molecular dynamics, revealing insights into phase separation, clustering, and transport properties under various conditions.

Contribution

It provides a comprehensive analysis of static and dynamic properties near criticality, including phase diagram, clustering, and transport, for a GEM-based ultrasoft particle mixture.

Findings

Identification of the critical point and phase diagram

Detailed analysis of cluster formation and composition

Temperature dependence of diffusivity and shear viscosity

Abstract

We investigate the static and the dynamic properties of an binary, equimolar, size-symmetric mixture of ultrasoft particles in the vicinity of the critical point of the system. Based on the generalized exponential potential (GEM) of order four for the particle interaction and using extensive molecular dynamics simulations in the canonical ensemble we investigate the above mentioned properties for various scenarios: we consider several super- and subcritical states, we expose the system to rapid quenches and to external shearing forces. Based on an accurate determination of the phase diagram and of the location of the critical point we study the static structure of the system in terms of particle-based radial distribution functions. As systems of GEM particles are prone to cluster formation we complement these investigations by a detailed analysis of the composition of the clusters and of their spatial correlations for the different scenarios introduced above. Furthermore we analyse the temperature dependence of the diffusivity of the particles and of the shear viscosity of the system. All these data provide a detailed and profound insight into the properties of the system under phase separation conditions and near criticality.