Enhanced mixing of intrinsic states in deformed Hf nuclei

Excited low-spin, nonyrast states in {sup 170,172,174}Hf were populated in {beta}{sup +}/{epsilon} decay and studied through off-beam {gamma}-ray spectroscopy. New coincidence data allowed for a substantial revision of the level schemes of {sup 170,172}Hf and a confirmation of the level scheme of {sup 174}Hf. 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{sup +} states, this mixing is followed and studied. The resulting mixing matrix elements are found to be {approx}30 keV - an order of magnitude larger than estimated previously for nearby nuclei. In the case of {sup 170}Hf, the 2{sub {beta}}{sup +} and 2{sub {gamma}}{sup +} level are shown to be completely mixed.