Superdeformed multi-quasiparticle high-K states and possible isomers in Pb and Po isotopes

Configuration-constrained potential-energy-surface calculations have been performed to investigate multi-quasiparticle high-K states built on superdeformed minima in Pb-192,Pb-194,Pb-196 and Po-198. The calculations predict that Pb-196 and Po-198 would be favorable candidates for the observation of low-lying superdeformed two-and four-quasiparticle high-K states. The possible decay paths and lifetimes that could lead to isomers are evaluated in detail for Pb-196. Comparisons between the predictions and previous observations of octupole-vibrational excitations indicate also that bands built on superdeformed high-K intrinsic states may compete with the octupole-vibrational mode in this mass region. The quadrupole moments of both the collective and intrinsic excitations are analyzed.