Effects of the range of the potential on the structure and dynamics of two-dimensional Coulomb clusters

Abstract

The structure, dynamics, and thermodynamics of finite systems of two-dimensional particles interacting mutually through a shielded Coulomb potential, V(r) = e((-kappa r))/r, and bound together by an isotropic parabolic trap, are investigated by means of global optimization and simulation methods. As the range of the potential decreases, or as kappa increases, the number of distinct minima rapidly increases for a given size and the cluster generally shrinks. Looking more specifically at selected sizes below 50, non-monotonic cluster size effects seem to dominate the energetics, chaotic dynamics, and thermodynamics, even though the melting point is weakly affected by the range of the potential.