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 Hf170,172 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+γlevel are shown to be completely mixed
