Properties of the rotational bands in Er-161

High-spin states in Er-161 have been studied experimentally using the Nd-150(O-16, 5n) reaction at a beam energy of 86 MeV. The 5/2(+)[642], 3/2(-)[521], and 11/2(-)[505] bands are extended up to high-spin states, and particularly the alpha = -1/2 branch of the ground state 3/2(-)[521] band is revised significantly. The relatively enhanced E1 transitions from the 3/2(-)[521] band to the 5/2(+)[642] band are observed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and near-prolate shape and triaxial deformation are proposed to the 3/2(-)[521] and 5/2(+)[642] bands, respectively. Signature inversion occurs in the 3/2(-)[521] band after the band crossing in Er-161, and the systematics of the signature inversion associated with the 3/2(-)[521] configuration are discussed. By analyzing the properties of the relatively enhanced E1 transitions, it is found that the R(E1/E2) values show angular momentum dependence before the band crossing, and these enhanced E1 transitions could be attributed to octupole softness.Physics, NuclearSCI(E)6ARTICLE3null8