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

Abstract

We investigate the static and the dynamic properties of a 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 supercritical and subcritical states, and 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 with a detailed analysis of the composition of the clusters and of their spatial correlations for the different scenarios introduced above. Furthermore, we analyze the temperature dependence of the diffusivity of the particles and 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.