Determination of the structure factor for the rare gas fluids based on the ORPA theory and LIR equation of state

Author： Nikoofard Hossein Esmaili Bibi Asma

ISSN： 1362-3028

Source： Molecular Physics, Vol.111, Iss.8, 2013-04, pp. : 992-999

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Abstract

Linear isotherm regularity is applied to generate an expression for the direct correlation function (DCF), based on the optimized random-phase approximation theory. We use the Lennard-Jones potential in the modelling of real fluids, in which its molecular parameters are state-dependent. Based on the perturbation theory, we assume that the core contribution of the DCF is related to the geometric effect via a linear form, which arises from the excluded volume, and the tail contribution is related to the long-range intermolecular interactions of the system via a non-linear form. We use this model to predict the behaviour of the structure factor, S(k), in a wide range of k values for the xenon and krypton liquids. Finally, we compare our results with the experimental and theoretical data available in literature. The model is also successful in the presentation of the Ornstein-Zernike behaviour of S(k) at the low-k region.