THE ELECTRICAL DOUBLE-LAYER IN WALL-WALL HYPERNETTED-CHAIN APPROXIMATION WITH BRIDGE FUNCTIONS

The wall-wall Ornstein-Zernike equation is formulated for the case of charged walls in a primitive model electrolyte. Numerical results are presented for the modified hypernetted chain (HNC) closure, which includes the effects of ion size and correlations. The bare HNC gives attractions between like-charged surfaces rather too readily, but this is ameliorated by the inclusion of the first bridge diagram. The singlet approach is shown to be accurate in divalent electrolyte, and in the large separation asymptotic regime. The method is less reliable in dilute monovalent electrolyte.