Multi-quasiparticle excitation: Extending shape coexistence inA~190neutron-deficient nuclei

Abstract

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 ${10}^{\ensuremath{-}}$ states in polonium isotopes, which indicate long-lived isomers.