An analytical longitudinal dielectric function of primitive electrolyte solutions and its application in predicting thermodynamic properties

In this paper, the longitudinal dielectric function ϵl(k) of primitive electrolyte solutions is discussed. Starting from a modified mean spherical approximation, an analytical dielectric function in terms of two parameters is established. These two parameters can be related to the first two decay parameters k1,2 of the dielectric response modes of the bulk system, and can be determined using constraints of k1,2 from statistical theories. Furthermore, a combination of this dielectric function and the molecular Debye-Hückel theory[J. Chem. Phys. 135(2011)104104] leads to a self-consistent mean filed description of electrolyte solutions. Our theory reveals a relationship between the microscopic structure parameters of electrolyte solutions and the macroscopic thermodynamic properties, which is applied to concentrated electrolyte solutions.