Nonprimitive electrolyte near a charged wall: Generalized mean spherical approximation

We consider a mixture of charged hard spheres (the ions) and dipolar hard spheres (the solvent) near a uniformly charged impenetrable wall (the electrode). This is a simple model which takes into account some of the mean microscopic interactions which appear at an electrode-electrolyte interface. We present some results for the structural and electrostatic properties of this model obtained using the generalized mean spherical approximation where the Ornstein-Zernike equation is coupled with a parameterized expression for the direct correlation function. These parameters are chosen by requiring that the correlation functions and their derivatives satisfy the linearized version of the hypernetted chain approximation. The resulting ionic and potential profiles and polarization density show that there is a layering of sheets of alternating sign near the electrode. The resulting differential capacitance curves are more featureless. © 1983 Elsevier Sequoia S.A.