Distribution of ions around a charged sphere

Using a new method of calculating the effects of excluded volume, the authors evaluate the distribution of counterions around a charged sphere in thermal equilibrium. In regions of high concentration a saturation of the ion density is found, which is absent in the more conventional Gouy-Chapman model. At the same time the saturation effect of the potential (a property of the Gouy-Chapman model) is removed, giving significant corrections to the values of the potential and concentration at the surface of the sphere.