Percolation of three-dimensional square-well fluid mixtures

Abstract

We study the percolation threshold of 3-dimensional attractive square-well fluid equimolar binary mixtures using Monte Carlo computer simulation. We examine the percolation threshold of the mixture and also of the two components separately. The total density at the percolation threshold considering each species separately is higher than that of the whole system to an extent depending on the molecular parameters. The relative interaction strengths of the two species can have a pronounced influence on their percolation thresholds, especially as temperature decreases.

For most significant interaction ranges, the percolation threshold of both components decreases with temperature. In the high temperature (geometry dominated) limit, the greatest increase in subspecies percolation threshold above that of the whole system appears for an interaction distance of ∼ 1·5σ, where σ is the diameter of the hard-core. For cut-off distances less or greater than this the percolation threshold of the subspecies is closer to that of the whole system.