Analytical implementation and critical tests of fluid thermodynamic perturbation theory

We appreciably broaden the scope of existing thermodynamic perturbation theory for pure fluids in several ways. Analytical approximation strategies are combined to express the thermodynamic properties of fluids in analytical and/or algebraic form and applied to a generalized class of pair potentials. The results are illustrated by comparing previously reported simulation measurements with our predictions obtained using a new class of generalized Lennard-Jones potential functions with independently adjustable repulsive and attractive length scales. Results are also obtained for various purely repulsive fluids, including inverse-power potentials with exponents ranging from 12 to 72 and a Lennard-Jones repulsive reference fluid. Applications to argon (Lennard-Jones) and C60 (Girifalco potential) are used to probe the limits of applicability of first-order perturbation theory to systems with very short range attractive potentials. Furthermore, we discuss the role of these new results in a number of additional applications.