MONTE CARLO SIMULATION OF MESOSCOPIC PHASE STRUCTURES IN THE NEAR-CRITICAL FLUID USING A “SLENDER STICK” CELL

Abstract

A novel “slender stick” cell was designed to accomplish the unachievable visualisation of fluids' mesoscopic phase behaviour in its near-critical state by using Monte Carlo simulations within the grand canonical ensemble. The simulation clearly showed the two-phase nature, viz., droplets and voids, of Xe just above its critical point (Tr = T/Tc = 1.01 and Pr = P/Pc = 1.09). The average sizes of supercritical Xe local structures were determined from the cluster size distributions, which agreed well with the published hydrodynamic radii of clusters obtained experimentally through optical methods. The cluster diameter monotonously increased with the fluid density at a constant temperature (Tr = T/Tc = 1.01).
 Keywords: Monte Carlo simulation, Mesoscopic structure, Xe, Near-critical state, cluster radii