Decays of 2.45-h 178Ta/sup m/ and 23.8-min 178Lu/sup m/ to the K/sup π/ = 8- levels in 178Hf

The decays of the high-spin isomers of 178Ta (2.45 h) and 178Lu (23.8 min) to the two strongly admixed K/sup π/ = 8- states in 178Hf were reinvestigated. The main features of the previously reported decay schemes are confirmed and several long-standing ambiguities are resolved. The results of this investigation indicate that the 1147-keV level is largely the two-neutron state and the 1479-keV level is largely the two-proton state in 178Hf. They are found to be 34% admixed with one another. This mixing value is in good agreement with the value deduced from the M1/E2 cascade ratios of the 1147-keV band and from the comparison of the E1 (ν = 7) hindrance factors of these two states in this mass region. The band-mixing matrix element for these two states was found to be in agreement with the recent theory which introduces the residual neutron-proton interaction to account for the mixing. The spin-parity of 178Lu/sup m/ (23.8 min) was deduced to be K/sup π/ = 9- with a possible Nilsson configuration of 9/2- [514] /subp/, 9/2+ [624] /subn/