Spinodal fractionation in a polydisperse square-well fluid

Spinodal fractionation in a polydisperse square-well fluid.

Using kinetic Monte Carlo simulation, we model gas-liquid spinodal decomposition in a size-polydisperse square well fluid, representing a "near-monodisperse" colloidal dispersion. We find that fractionation (demixing) of particle sizes between the phases begins asserting itself shortly after the onset of phase ordering. Strikingly, the direction of size fractionation can be reversed by a seemin...

Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid.

We dynamically simulate fractionation (partitioning of particle species) during spinodal gas-liquid separation of a size-polydisperse colloid, using polydispersity up to ~40% and a skewed parent size distribution. We introduce a novel coarse-grained Voronoi method to minimise size bias in measuring local volume fraction, along with a variety of spatial correlation functions which detect fractio...

Isospin fractionation : equilibrium versus spinodal decomposition

Pair Distribution Function of a Square-Well Fluid

The properties of the ground state of liquid He are studied using a correlated basis function of the form ∏ i<j ψ(rij). Here, ψ(r) is chosen as the exact solution of the Schrödinger equation for two He atoms. A hard-sphere plus an attractive square well is used as the interaction potential between He atoms. The pair distribution function is calculated using approximate integral methods, namely ...

Three-phase fractionation of polydisperse fluids

It is shown that the van der Waals free-energy of polydisperse fluids, as introduced previously ( L. Bellier-Castella, H. Xu and M. Baus, J. Chem. Phys. 113, 8337 (2000) ), predicts that for certain thermodynamic states (e.g. low temperatures and large polydispersities) the ordinary two-phase coexistences become metastable relative to a fractionation of the system into three phases, reducing th...