The mean spherical approximation for a dipolar Yukawa fluid

Abstract

Articles you may be interested inDevelopment of an equation of state for electrolyte solutions by combining the statistical associating fluid theory and the mean spherical approximation for the nonprimitive model Solution of the associative mean spherical approximation for a multicomponent dimerizing hard-sphere multi-Yukawa fluidThe dipolar hard sphere fluid ͑DHSF͒ is a useful model of a polar fluid. However, the DHSF lacks a vapor-liquid transition due to the formation of chain-like structures. Such chains are not characteristic of real polar fluids. A more realistic model of a polar fluid is obtained by adding a Lennard-Jones potential to the intermolecular potential. Very similar results are obtained by adding a Yukawa potential, instead of the Lennard-Jones potential. We call this fluid the dipolar Yukawa fluid ͑DYF͒. We show that an analytical solution of the mean spherical approximation ͑MSA͒ can be obtained for the DYF. Thus, the DYF has many of the attractive features of the DHSF. We find that, within the MSA, the Yukawa potential modifies only the spherically averaged distribution function. Thus, although the thermodynamic properties of the DYF differ from those of the DHSF, the MSA dielectric constant of the DYF is the same as that of the DHSF. This result, and some other predictions, are tested by simulations and are found to be good approximations.

Magnetization and susceptibility of ferrofluids

“…where µ DY is the chemical potential of the DY fluid [7,8]. By eliminating the chemical potential the equilibrium grand canonical potential can be expressed as…”

“…where f DY = F DY /V is the free energy density of the homogeneous and isotropic DY fluid [7,8]. Due to Ω = −pV the corresponding pressure of an equilibrium phase as a function of the density and temperature is…”

“…Since dω∆α(ω) = 0 only the second-and higher-order direct correlation functions provide nonzero contributions to the functional βF ex,a DY . In the following we approximate the second-order direct correlation function of a DY fluid by the corresponding MSA solution due to Henderson et al [7]: (10) (see Eq. (3)) with the rotationally invariant function…”

“…Based on previous experience [7,8], here we substitute the Lennard-Jones potential by a hard core Yukawa potential. For a homogeneous isotropic dipolar Yukawa (DY) fluid this substitution provides the valuable benefit that one can solve analytically the corresponding Ornstein-Zernike equation within the mean spherical approximation (MSA).…”

Magnetic Properties of Colloidal Suspensions of Interacting Magnetic Particles

“…Henderson, Boda, Szalai, and Chan [70,71] apply the MSA, the theory by Tani et al [26], and Monte-Carlo calculations to dipolar Yukawa particles with a hard core. Again, the results are found to be similar to those for dipolar hard spheres and Stockmayer particles.…”