The lifetimes of 12 excited states in ${}^{134}\mathrm{Nd}$ were measured with a high precision by means of the GASP spectrometer applying the coincidence recoil-distance Doppler-shift method. The ${}^{110}\mathrm{Pd}{(}^{28}\mathrm{Si},xnyp)$ reaction was used at a beam energy of 125 MeV. The data were analyzed with the differential decay curve method and the derived lifetimes were used for a sensitive test of various nuclear models. The transition quadrupole moments ${(Q}_t)$ in the ground state band agree nicely with the predictions of both the rotor model and the O(6) symmetry of the interacting boson approximation up to the $4_g^{+}$ state of ${}^{134}\mathrm{Nd}.$ The $Q_t$ values for the $8_g^{+},$ ${10}_{S1\mathrm{}}^{+},$ and ${12}_{S1\mathrm{}}^{+}$ states, however, give evidence for a strong change of the nuclear deformation. The lifetimes of 12 low lying yrast states in the ${}^{130,131,132}\mathrm{Ce},$ ${}^{133,134}\mathrm{Pr},$ and ${}^{135}\mathrm{Nd}$ nuclei have been also determined.

• Received 15 January 1999

DOI:https://doi.org/10.1103/PhysRevC.60.034301