Properties of small Ar<i>N</i>−1K+ ionic clusters

Abstract

A self-consistent formalism is developed that dynamically determines the thermodynamic properties of ionic clusters, based upon a many-body potential, without an a priori designation of the equilibrium structures. The system studied is an aggregate consisting of a single closed shell K+ ion and N−1 isoelectronic argon atoms. The clusters form crystallites at low temperature, with melting transitions at T=8, 19, and 11 K, for N=5, 7, and 13, respectively. They spontaneously disassociate at T=125, 98, 80, and 48 K, for N=3, 5, 7, and 13, respectively. The results confirm experimental evidence that indicates ionic clusters become less stable with increasing N. The crystallite structures formed by these four different systems are isosceles triangle, skewed form, octahedron with the ion in the middle, and icosahedron with the ion in the middle.