Why is Gibbs free energy not used in Statistical Associating Fluid Theory (SAFT) Equation of State (EoS)?

Question

reinmelk3iu · Accepted Answer

Statistical Associating Fluid Theory (SAFT) Equation of State is a popular approximate method, based on perturbation theories of Statistical Mechanics, able to incorporate the effects of molecular association. As a perturbative approach, it is not a simple fitting of experimental-based data. It relies on a good knowledge of the physical properties of a reference system. In its present implementations, the Hard Spheres (HS) fluid plays the role of the reference system.In principle, every choice of the basic thermodynamic variables is allowed, determining which thermodynamic potential should be used (Gibbs free energy if the independent variables are P,T,N, or Helmholtz free energy if the variables are V,T,N).It turns out that most of the data for HS systems are available or have been obtained within the canonical ensemble. This naturally drives SAFT approaches to use the Helmholtz free energy as the thermodynamic potential. Of course, this is not a limitation because every thermodynamic potential contains the full information about the thermodynamics of the system.

Why is Gibbs free energy not used in Statistical Associating Fluid Theory (SAFT) Equation of State (EoS)?

Answered question

Answer & Explanation

New Questions in Thermal Physics