Landau description for an atomic screened system: the charge symmetry breaking effect A.L.A. Penna, J.B. Diniz and F.A. Oliveira Eur. Phys. J. D, 56 1 (2010) 27-31 Published online: 06 November 2009 DOI: 10.1140/epjd/e2009-00273-7