High- K isomers in neutron-rich hafnium nuclei at and beyond the stability line

Pulsed {sup 238}U and {sup 208}Pb beams have been used to populate multi-quasiparticle high-K isomers in neutron-rich hafnium isotopes at and beyond the line of {beta}-stability, via inelastic excitation and transfer. Spectroscopic properties and configuration assignments of several new high-K isomers are compared with earlier theoretical predictions. A striking example of the robustness of the K quantum number is demonstrated by the observed competition between E1 and E3 decay modes in {sup 180}Hf, the heaviest stable isotope of the element. {copyright} {ital 1999} {ital The American Physical Society}