Collective bands in odd–odd 118I Original Research Article

The excited states of the doubly-odd nucleus 118I were investigated by using in-beam gamma-ray spectroscopy with the 103Rh (18O, 3n) 118I reaction at an energy of 85 MeV. The beam was provided by the 12UD tandem accelerator at the University of Tsukuba. Several collective bands were identified and their excitation energies were definitely established. The positive-parity collective bands based on the πh11/2νh11/2 configuration and the negative-parity bands based on the πh11/2νg7/2 configuration were newly assigned. An inversion between the favored and unfavored states in the πh11/2νh11/2 band was observed below I=17.5ℏ. The excitation energy of the 7− isomer with T1/2=8.5 m was found to be at 188.8 keV.