title: Influence of a defect particle on the structure of a classical two-dimensional cluster.
abstract: A system of classical charged particles interacting through a Coulomb repulsive potential which are confined in a two-dimensional parabolic trap is studied. We allow one or two particles, called defect particles, to have a different mass and/or charge than the other particles. The structure of the whole system depends on the mass and the charge of the defects and the total number of particles in the system. The ground state configurations are investigated and phase diagrams are constructed, which explain the recent experimental results of Phys. Rev. E 64, 11 603 (2001)]]. We found that several of the experimental configurations are metastable and that replacing the Coulomb interparticle potential by an inversely quadratic one has only a minor effect on the results.
authors.affiliation: Departement Fysica, Universiteit Antwerpen (Campus Drie Eiken), Universiteitsplein 1, B-2610 Antwerp, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Nelissen
authors.forename: B
authors.initials: B
authors.lastname: Partoens
authors.forename: F M
authors.initials: FM
authors.lastname: Peeters