LABORATORI NAZIONALI DI LEGNARO
The g factors of several low-lying excited states of neutron-rich 101Zr and 103,105Mo have been measured for the first time. The isotopes were produced by the spontaneous fission of a 252Cf source, sandwiched between two magnetised iron foils and placed at the centre of the gammasphere spectrometer. The g factors were inferred from Larmor precessions deduced from the measurement of time-integral perturbed angular-correlation functions. The magnitude and sign of the quantity (gK − gR)/Q0 were determined from the mixing ratios measured for the 3/2[411] and 5/2[532] rotational bands in 101Zr and 103,105Mo. The combination of this quantity with the measured g factors permitted the separation of the particle-rotor parameters gK and gR for each band. The comparison of the extracted gK factors to Nilsson Model predictions confirm current band assignments and are consistent with an axially symmetric picture of these nuclei at low spins. The possible effect of triaxial deformation on the measured magnetic moments was investigated in the rigid triaxial rotor-plus-particle framework. The calculations suggest that triaxial deformation plays a stronger role in the Mo than in the Zr isotopes, but that triaxiality is likely to be dynamic. The extracted gR factors are consistently smaller than the Z/A limit, in agreement with neighbouring even-even nuclei.

DATA: 19-09-2005