Journal of Physical Studies 11(2), 165–177 (2007) DOI: https://doi.org/10.30970/jps.11.165 POLYDISPERSE HARD-SPHERE YUKAWA CHAIN FLUID: HIGH TEMPERATURE APPROXIMATION S. P. Hlushak, Yu. V. Kalyuzhnyi Institute for Condensed Matter Physics, 1 Svientsitskoho St., 79011 Lviv, Ukraine

The high temperature approximation (HTA) for a polydisperse hard-sphere Yukawa chain fluid is proposed. A closed form analytical expression for Laplace transform of the reference system site-site radial distribution function, which is used as an input in the theoretical scheme developed, is obtained from the solution of the averaged version of the multidensity Ornstein-Zernike equation. It is demonstrated that in the frames of the HTA polydisperse hard-sphere Yukawa chain fluid model belongs to a class of "truncatable free energy models", i. e. the models with thermodynamical properties (Helmholtz free energy, chemical potential and pressure) defined by a finite number of generalized moments. The accuracy of the theory is accessed by comparison of its liquid-gas phase diagram predictions obtained in the monodisperse limiting case, with the corresponding predictions of the statistical associating fluid theory for the potentials of variable range (SAFT-VR) and thermodynamic perturbation theory dimer (TPTD).

PACS number(s): 61.20.Gy, 61.25.Em, 61.25.Hq, 83.80.Rs

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