A parametrisation of the direct correlation function for the square-shoulder fluid

Theoretical approaches to the structural properties of the square-shoulder fluid

“…Zhou and Solana [19] also reported MC simulations for this system and theoretical results based on a bridge function approximation to close the OZ equation. Further simulation data for the SS fluid and a parametrisation of the direct correlation function which quantitatively agrees with the numerical solution of the OZ equation with the PY closure were presented by Guillén-Escamilla et al [21].…”

“…In this paper we have revisited three analytical procedures [23,24,29,30,32] to obtain the structural properties of SS fluids and compared their predictions against simulation results [12,19,21] in order to assess their merits and limitations. All these approaches have in common the fact that they are analytical in Laplace space and reduce in two independent limits [see Equations (2a) and (2b)] to the PY result for the HS fluid, although only the RFA does it in a third limit [see Equation (2c)].…”

“…In order to assess the value of the three previous theoretical approximations for the structural properties of SS fluids, in this section we carry out a comparison between the results derived from them and those obtained from simulation [12,19,21]. Although we have made such a comparison with many other data, in Figures 1-7 we only show graphs of g(r) vs r for some representative cases.…”

“…Figure 7. Radial distribution function g(r) as a function of distance r for an SS fluid having λ = 1.5, T * = 2 and η = 0.4189 (ρσ 3 = 0.8) as obtained from the FMSA (dashed line), the SEXP/FMSA (dotted line), the RFA (solid line) and simulation data from Ref [21]. (circles).…”

Structure of the square-shoulder fluid

“…(2) This purely repulsive potential, apparently considered first by Hemmer and Stell 40 years ago [21], has been the subject of recent attention [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. On the one hand, it may lead to an isostructural solid-solid transition [22], to a fluid-solid coexisting line with a maximum melting temperature [23], to unusual phase behaviour [24][25][26] and to a rich variety of (self-organised) ordered structures [27][28][29][30].…”