Similarity law and critical properties in ionic systems.

Abstract

Using molecular simulations, we determine the locus of ideal compressibility, or Zeno line, for a series of ionic compounds. We find that the shape of this thermodynamic contour follows a linear law, leading to the determination of the Boyle parameters. We also show that a similarity law, based on the Boyle parameters, yields accurate critical data when compared to the experiment. Furthermore, we show that the Boyle density scales linearly with the sizeasymmetry, providing a direct route to establish a correspondence between the thermodynamic properties of different ionic compounds.

The Line of the Unit Compressibility Factor (Zeno-Line) for Crystal States

“…Below we also will call it the Z-line. The calculations for some metals and ionic systems in liquid phase − confirm that the Z-lines are also straight in these cases. Analogous study , for some model systems, have shown that behavior of the Z-line depends on the range of the interparticle potential: it became nonstraight for the cases of too-long-ranged or too-short-ranged potentials.…”

Hard-core attractive Yukawa fluid global isomorphism with the lattice gas model

“…In this respect numerical methods for calculating the grand canonical-function are of great importance because they allow to trace the dependence of thermodynamic quantities on the parameters of various interaction potentials 14,15 . The results show that equation (2) valid even for ionic liquids and liquid metals [16][17][18][19][20] .…”

Global isomorphism approach: Attractive Yukawa fluid, 2D case

“…Figure 1: Projective transformation applied to Onsager's solution (19). The empty circles are the data of the numerical simulations [33] normalized to the Zeno-element (red) parameters ( 16) and (18) Figure 2: Comparison of the tangent to the binodal with the Zeno line and the Zenoelement for λ = 1.0 (a) and λ = 1.8 (b), numerical data from the work [33]. The blue line is tangent to the binodal, the green is the Zeno-element, the orange is the Zeno line.…”

“…is approximately straight for many fluid systems [15,16], [17,18] and can be represented by the equation:…”