Towards an analytical theory for charged hard spheres

Abstract

Ion mixtures require an exclusion core to avoid collapse. The Debye Hueckel (DH) theory, where ions are point charges, is accurate only in the limit of infinite dilution. The mean spherical approximation (MSA) is the embedding of hard cores into DH, and is valid for higher densities. The properties of any ionic mixture can be represented by the single screening parameter Γ which for the equal ionic size restricted model is obtained from the Debye parameter κ. This Γ representation, the binding mean spherical approximation (BIMSA), is also valid for complex/associating systems, such as the general n-polyelectrolytes. The BIMSA is the only theory that satisfies the infinite dilution limit of the DH theory for any chain length. Furthermore, the contact pair distribution function calculated from our theory agrees with the Monte Carlo of Bresme ea.(Phys. Rev. E, 1995, 51, 289). © L.Blum, D.V.P.Veloz.