Pair-correlation model temperature-dependent

A universal quasi-chemical model (UNIQUAC) (Abrartts and Prarrsnitz, 1975) has been successfully applied for the correlation of several LLE systerrrs. This model depends on optimized interaction parameters between each pair of components in the system, which can be obtained by experiments. The UNIQUAC eqrration can be fitted to the experimental composition by optimizing the interaction parameter (a. and a ). The optimized interaction parameters can also be correlated with temperature. 

The mean field approximation captures some essence of particle interactions (this is what sets it apart from the ideal gas model) but it neglects correlations by its assumption that each particle interacts with an unperturbed equilibrium distribution of particles. The accuracy of the mean field depends on the strength of correlations [9], Among theoretical models for which the mean field is considered exact are hard-spheres in the infinite dimension [10], Another example are particles with the pair interaction U(r) = X u Xr) taken to the limit A 0, and where the function u(r) is bounded and of finite range [11], For experimentally relevant systems A remains finite, and so the corrections to the mean field are always present and real. An example of a system regarded as weakly correlated is the Gaussian core model at room temperature. For this model and these conditions the mean field approximation is a reliable theoretical description [12]. 

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