title: Structure and correlations in two-dimensional classical artificial atoms confined by a Coulomb potential.
abstract: The ordering of N equally charged particles (-e) moving in two dimensions and confined by a Coulomb potential, resulting from a displaced positive charge Ze is discussed. This is a classical model system for atoms. We obtain the configurations of charged particles which, depending on the value of N and Z, may result in ring structures, hexagonal-type configurations, and for N/Z approximately 1 in an inner structure of particles which is separated by an outer ring of particles. For N/Z<<1, the Hamiltonian of the parabolic confinement case is recovered. For N/Z approximately 1, the configurations are very different from those found in the case of a parabolic confinement potential. A hydrodynamic analysis is presented in order to highlight the correlations effects.
authors.affiliation: Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-760 Fortaleza, Ceará, Brazil. paiva@fisica.ufc.br
authors.forename: W P
authors.initials: WP
authors.lastname: Ferreira
authors.forename: A
authors.initials: A
authors.lastname: Matulis
authors.forename: G A
authors.initials: GA
authors.lastname: Farias
authors.forename: F M
authors.initials: FM
authors.lastname: Peeters