The rotational quadrupole moment of continuum-states at high-spin in 164Yb

The lifetime of the unresolved transitions forming the rotational quasi-continuum spectra has been measured in Yb-164 using the Doppler shift attenuation method. The valley structure in E-gamma 1 x E-gamma 2 spectra was analysed using a new technique, based on fluctuation patterns, which provided for the first time experimental lifetimes for rotational damped transitions. The present results show, as predicted by the rotational damping model, that the collectivity persists for highly excited bands. In particular, agreement is found between the experimental results, for discrete and damped transitions, and the predictions corresponding to Q(t) = 5.5 eb, for the entire interval of gamma-ray energies studied.