Configuration-constrained nuclear shape calculations are used to show that reinforcing neutron and proton orbital structures create exceptional conditions for the formation of multiquasiparticle isomers in neutron-rich hafnium isotopes, with axially symmetric, prolate shapes. Highly excited, long-lived states are predicted. However, at angular momenta close to 40$ħ,$ orbital alignment effects for collective oblate rotation lead to a deep potential minimum that competes energetically with the prolate multiquasiparticle states.

• Received 14 October 1999

DOI:https://doi.org/10.1103/PhysRevC.62.014301