Microscopic descriptions of superdeformed bands with the Gogny force: Configuration mixing calculations in the A similar to 190 mass region - art. no. 054301

A quantal Hamiltonian (H) over cap(coll) expressed in terms of the five col lective quadrupole coordinates is built for eight nuclei (Hg-190,Hg-192,Hg- 194, Pb-192,Pb-194,Pb-196, and Po-196,Po-198) which display secondary minim a at large elongation in their potential energy surface. These surfaces as well as the tensor of inertia entering (H) over cap(coll) are deduced from constrained Hartree-Fock-Bogotiubov calculations based on Gogny force. A tw o-center basis method employed to solve (H) over cap(coll) is presented. Th e stability of predicted collective spectra is discussed. Yrast and vibrati onal pi=+ superdeformed (SD) bands are predicted together with collective b ands at normal deformation (ND). The predicted yrast SD bands at low spin d isplay properties which compare favorably with experimental information. Qu ite good agreement is in particular obtained for the isomeric energies of n uclei for which the link between SD and ND levels is experimentally known. Among the excited SD bands which are here predicted, those built on top of beta vibrations are lower in energy. Only for the Po-196,Po-198 isotopes ar e these excitation energies falling in the low energy range E similar to 0. 8-1.0 MeV. These properties should favor an experimental discovery of P-vib rational SD bands in the A similar to 190 mass region. [S0556-2813(99)03709 -7].