THEORETICAL-STUDY OF (NACL)(N) CLUSTERS

In this paper we present the theoretical results obtained for (NaCl)(n) clusters with n less than or equal to 19, using the ab initio perturbed-ion (PI) model. That model was first developed for the study of ionic crystals and it has been adapted here to study clusters. Within the PI model we can determine the total energy of the cluster as a function of the position of the atoms in the cluster and minimizing the total energy with respect to those positions we can obtain the ground state geometry and other related properties. The results for the equilibrium geometries are compared with calculations using pair potentials and with other ab initio results. The study of the relative stabilities of clusters with different numbers of molecules shows that the clusters are especially stable for n = 4, 6, 9, 12, 15, 16 and 18 molecules, in good agreement with experimental results. We also study some electronic properties, as for instance ionization potentials.