Multi-quasiparticle high-$K$ states in neutron-deficient mercury, lead, and polonium isotopes have been investigated systematically by means of configuration-constrained potential-energy-surface calculations. An abundance of high-$K$ states is predicted with both prolate and oblate shapes, which extends the shape coexistence of the mass region. Well-deformed shapes provide good conditions for the formation of isomers, as exemplified in ${}^{188}\mathrm{Pb}$. Of particular interest is the prediction of low-lying ${10}^{-}$ states in polonium isotopes, which indicate long-lived isomers.

• Received 9 July 2010

DOI:https://doi.org/10.1103/PhysRevC.82.044314