Equation of state and critical point behavior of hard-core double-Yukawa fluids

Abstract

A theoretical study on the equation of state and the critical point behavior of hard-core double-Yukawa fluids is presented. Thermodynamic perturbation theory, restricted to first order in the inverse temperature and having the hard-sphere fluid as the reference system, is used to derive a relatively simple analytical equation of state of hard-core multi-Yukawa fluids. Using such an equation of state, the compressibility factor and phase behavior of six representative hard-core double-Yukawa fluids are examined and compared with available simulation results. The effect of varying the parameters of the hard-core double-Yukawa intermolecular potential on the location of the critical point is also analyzed using different perspectives. The relevance of this analysis for fluids whose molecules interact with realistic potentials is also pointed out.

On Molecular-Based Equations of State: Perturbation Theories, Simple Models, and SAFT Modeling

“…A typical example of such theoretical equations are the results of the TPT applied to various primitive models [39,40]. Considering realistic models, truly theoretical EoS's obtained by a perturbation expansion are also available, e.g., for the square-well fluid [6,7] or Yukawa fluid [16,47,48]. For further discussion, see section 3.1.…”

“…The most common choice used to be the LJ potential for which several analytic equations of state are available [2,78,79]. The hard-core Yukawa can also be a potential choice for the same reason [47,48]. It is also used for the description of screed Coulombic interactions while the Sutherland potential is useful for systems with multipolar interactions.…”