Enhanced Mixing of Intrinsic States in Deformed Hf Nuclei
Excited low-spin, nonyrast states in 170,172,174Hf were populated in β+ /∈ decay and studied through off-beam γ -ray spectroscopy. New coincidence data allowed for a substantial revision of the level schemes of 170,172Hf and a confirmation of the level scheme of 174Hf. The Hf isotopes represent a unique situation in which a crossing of collective intrinsic excitations occurs, enhancing significantly the effects of mixing. Using branching ratios from excited 2+ states, this mixing is followed and studied. The resulting mixing matrix elements are found to be ∼30 keV—an order of magnitude larger than estimated previously for nearby nuclei. In the case of 170Hf, the 2+β and 2+γ level are shown to be completely mixed.