Mixing effects on K-forbidden transition rates from the 6+ isomers in the N = 104 isotones

The problem of the very different E2 decay rates from the two-quasineutron K(I ) = 6(+) isomers in the N = 104 isotones (172)Er, (174)Yb, (176)Hf, and (178)W is investigated using the triaxial projected shell model with inclusion of multi-quasiparticle configurations. It is demonstrated that the highly K-forbidden transition from the 6(+) isomer to the ground-state band is sensitive to mixing with the 6(+) state of the l-vibrational band. Thus the inter-band transitions, and lifetimes, depend on the relative position of the l-band and the isomeric state in each isotone.