Quadrupole moment measurements for strongly deformed bands inHf171,172

Abstract

A lifetime experiment, using the Doppler-shift attenuation method, has been performed at Gammasphere to measure the transition quadrupole moments Q t of strongly deformed bands in 171 Hf and 172 Hf. The measured value of Q t ∼ 9.5 e b for the band labeled ED in 171 Hf strongly supports the recent suggestion that this sequence and several structures with similar properties in neighboring Hf isotopes are associated with a near-prolate shape with a deformation enhanced relative to that of normal deformed structures. The measured values of Q t ∼ 14 e b for the bands labeled SD1 and SD3 in 172 Hf confirm that these sequences are associated with a prolate superdeformed shape, a property inferred in earlier work from other measured characteristics of the bands. Similar bands in 173−175 Hf are also likely to be associated with superdeformed shapes. The observations are in contrast to predictions of cranking calculations performed with the ULTIMATE CRANKER code.

Interpretation of the high spin states inLu161: A paired and unpaired study

“…In the neighboring Hf (Z = 72) isotopes, evidences for TSD bands have also been presented [44][45][46][47]. The cranking formalism has predicted pronounced minima around (ε 2 ,γ ) ∼ (0.4,20 • ) which are caused by shell gaps for proton numbers Z = 71 and 72, and neutron numbers N = 94 and 97 [40,48].…”