Binding energy, microstructure, and shell model of Coulomb clusters

By computer-simulation and analytic studies for binding energies and microscopic shell structures, it is shown that Coulomb clusters assume particularly stable configurations at certain ``magic numbers'' of particles. Through analyses with the spherical Voronoi numbers, a special role that the icosahedral geometry plays in shaping the particle configurations on the spherical surfaces is elucidated. Gross features in the cluster structures, such as the shell radii and intershell partition of particles, are well accounted for by an appropriate shell model.