Structural and dynamical aspects of small three-dimensional spherical Coulomb clusters

An analysis of the structural and dynamical properties of small size three-dimensional clusters of classical charged particles confined in a spherical parabolic trap is presented. The ground state and the lowest metastable configurations are identified for Coulomb clusters consisting of N=4-100 particles. The eigenmode frequencies are investigated both for clusters with Coulomb and screened Coulomb interparticle interaction. The breathing mode frequency is analytically determined and is found to be the highest energy eigenmode and independent of the number of particles for the case of Coulomb inter-particle interaction