MULTIPLE BAND STRUCTURES AT HIGH ANGULAR-MOMENTUM IN I-115 - TOWARDS UNFAVORED BAND TERMINATION

Six new rotational bands have been established in 115I at high spin us ing the near symmetric Ni-60(Ni-58,3pgamma) reaction at 250 MeV. Sever al of the bands are observed to frequencies beyond HBARomega = 1.0 MeV (spin approaching 50HBAR). All the bands show a characteristic drop o ff in their dynamic moments of inertia with increasing spin. The low v alues at the highest spins are consistent with predictions for a band termination in which a gradual shape change from collective prolate to noncollective oblate occurs over many transitions. These smoothly occ urring terminations contrast with the abrupt ''favored'' terminations previously observed in this and other odd-A iodine nuclei.