The structure and volume of ion clusters in the restricted primitive model

Abstract

The structures of ion clusters have been investigated for the restricted primitive model in the low density limit. The calculations have been accomplished by a Monte Carlo integration over the probability function of the cluster configuration. The size of the clusters ranges from dimer to octamer. Properties related to the structure, such as the number of associating bonds, the cluster volumes and the multipole moments including ion polarizability, have been calculated. Two qualitatively different approaches for the Bjerrum distance have been investigated and compared with respect to its physical relevance. The Bjerrum distance is the crucial and arbitrary parameter in the ion cluster theory. As a result it was found that a considerable small constant Bjerrum distance is superior to Bjerrum's original temperature dependent approach.