Levels in /sup 146/Ce and the N=88 isotones

An investigation of the level structure of /sup 146/Ce following the beta decay of the low-spin isomer of /sup 146/La has been carried out at the ISOL facility TRISTRAN. The half-life for the low spin isomer is found to be 6.0+or-0.4s. A partial level scheme for /sup 146/Ce below 2 MeV is given. The level energies and some B(E2) values extracted from the data have been compared with IBA-2 calculations done entirely with extrapolated parameters from neighboring Z nuclei in order to check the predictive power of the model. Systematics of the Z=58 isotopes and N=88 isotones indicate that although /sup 146/Ce is more deformed than its isotones with z>or=60, the transition to the well-deformed region can probably more correctly be thought to occur after /sup 146/Ce, between N=88 and N=90, as it does for Z>or=60. The abrupt onset of deformation present in the higher Z isotopes is not seen in the Ce isotopes where the trend is found to be rather smooth throughout. (17 refs).