Phase behaviour of attractive and repulsive ramp fluids: integral equation and computer simulation studies

Abstract

Using computer simulations and a thermodynamically self consistent integral equation we investigate the phase behaviour and thermodynamic anomalies of a fluid composed of spherical particles interacting via a two-scale ramp potential (a hard core plus a repulsive and an attractive ramp) and the corresponding purely repulsive model. Both simulation and integral equation results predict a liquid-liquid de-mixing when attractive forces are present, in addition to a gas-liquid transition. Furthermore, a fluid-solid transition emerges in the neighbourhood of the liquid-liquid transition region, leading to a phase diagram with a somewhat complicated topology. This solidification at moderate densities is also present in the repulsive ramp fluid, thus preventing fluid-fluid separation.

29 pages, 10 figures

References in corpus (6)

• Excess entropy, Diffusivity and Structural Order in liquids with water-like anomalies
• Thermodynamics and Dynamics of the Two-Scale Spherically-Symmetric Jagla Model of Anomalous Liquids
• Structural Order for One-Scale and Two-Scale Potentials
• Metastable liquid-liquid coexistence and density anomalies in a core-softened fluid
• Relation between the Liquid-Liquid Phase Transition and Dynamic Behavior in the Jagla Model
• Thermodynamic and Dynamic Anomalies for Dumbbell Molecules Interacting with a Repulsive Ramp-Like Potential

Cited by in corpus (2)

• Anomalous phase behavior of a soft-repulsive potential with a strictly monotonic force
• Microscopic structure and thermodynamics of a core-softened model fluid from the second-order integral equations theory