Static Dielectric Function of a Model Classical Ionic Fluid

Abstract

The behaviour of the static dielectric function ε(k) a system of charged hard spheres has been studied, within the Mean spherical Approximation, for a wide range of values of the ionic size ratio α, packing fraction η, and plasma parameter Γ. The results presented are limited to the charge symmetric case.

We find that ε(k) already takes on negative values for Γ = 1 when the size of anions and cations are the same and η = 0.30. Packing and size difference become less significant as the value of the plasma parameter increases. As Γ increases in value ε(k) becomes negative over an increasing range of values of the wavenumber k. For given vaules of Γ and η, ε(k) is nearest to zero for a non-zero value of k when α = 1.0.

Key Words:

• Static dielectric function
• charged hard spheres