Band termination in I-123

High-spin states in the nucleus I-123 were populated by the Pd-110(O-16,p4n) reaction at 75 MeV. gamma-ray energies, intensities, gamma-gamma coincidences, and directional correlation ratios were measured. The rotational band built on the pi h(11/2) single-particle state was extended to spin I=35/2(-); at higher spin the level spacings and the feeding pattern were found to become irregular, indicating a sudden change of structure. The 39/2(-) state and a higher-lying 43/2(-) level were interpreted as aligned oblate states, in line with the systematics of the lighter odd-A iodine isotopes. Total Routhian surface calculations were performed and were found to support the occurrence of a band termination. Higher-lying levels that feed the h(11/2) band were identified, reaching spin I greater than or equal to 47/2 and an excitation energy of about 9 MeV.