Isomeric and collective structures in neutron-rich hafnium isotopes

The structures of isomeric and collective states in neutron-rich hafnium isotopes have been investigated within the paired cranked Nilsson-Strutinsky-Bogoliubov (CNSB), and the unpaired cranked Nilsson-Strutinsky (CNS) formalisms. We show that by combining these two models, a good understanding of the formation of multiquasiparticle prolate isomers is achieved. The calculations show at angular momenta $I\ensuremath{\ge}35$, well-deformed oblate collective rotation strongly competes energetically with the prolate noncollective states. Comparison is made with experimental data, where available, and with other model calculations.