The transition quadrupole moments, $Q_{ t}$, of rotational bands in the neutron-rich, even-mass $^{ 102-108}$Mo and $^{ 108-112}$Ru nuclei were measured in the 8 to 16 $\hbar $ spin range with the Doppler-shift attenuation method. The nuclei were populated as fission fragments from $^{ 252}$Cf fission. The detector setup consisted of the Gammasphere spectrometer and the HERCULES fast-plastic array. At moderate spin, the $Q_{ t}$ moments are found to be reduced with respect to the values near the ground states. Attempts to describe the observations in mean-field-based models, specifically cranked relativistic Hartree-Bogoliubov theory, illustrate the challenge theory faces and the difficulty to infer information on $\gamma $ softness and triaxiality from the data.
Categories: nucl-ex