ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We evaluate a number of current closure relations used in the integral equations for hard sphere fluids, such as the Percus–Yevick, Martynov–Sarkisov, Ballone–Pastore–Galli–Gazillo, and Verlet modified (VM) closures with respect to their abilities of satisfying the zero-separation theorems for hard spheres. Only the VM closure is acceptable at high densities (ρ∼0.7), while all fail at lower densities (lim 0〈ρ〈0.5). These shall have deleterious effects when used in perturbation theories, especially at low densities. To improve upon this, we propose a closure, ZSEP, that is flexible and suited to satisfying the known zero separation theorems [e.g., the ones for the cavity function y(0) and the indirect correlation γ(0), and others for their derivatives dy(0)/dr, etc.], plus the pressure consistency condition. This particular closure, after numerical solution with the Ornstein–Zernike equation, is shown to perform well at high densities (ρ∼0.9) as well as low densities (0.1〈ρ〈0.5) for the cavity function y(r), the pair correlation function g(r), and the bridge function B(r). Derived thermodynamic properties: pressure, isothermal compressibility, and chemical potential are also highly accurate. Comparison with available Monte Carlo data bears this out. We have formulated a "consistent'' and accurate integral equation theory for hard spheres over a wide range of density states. © 1995 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.469998
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