Ground state configurations and melting of two-dimensional non-uniformly charged classical clusters

We consider classical two-dimensional (2D) Coulomb clusters consisting of two species containing five particles with charge q(1) and five with charge q(2), respectively. Using Monte Carlo and molecular dynamics (MD) simulations, we investigated the ground state configurations as well as radial and angular displacements of particles as a function of temperature and their dependence on the ratio q = q(2)/q(1). We found new configurations and a new multi-step melting behavior for q sufficiently different from the uniform charge limit q = 1.