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In-beam γ spectroscopy of the stable nucleus 127 I has been studied experimentally using the 124 Sn( 7 Li, 4nγ ) 127 I reaction at a beam energy of 32 MeV. The high-spin level scheme of 127 I is extended significantly. Negative-parity levels built on the 11/2 − , πh 11/2 particle state are observed up to (35/2 − ) and described as a decoupled band, extending our knowledge of decoupled structures to the most neutron-rich stable iodine isotope. Two I = 2 yrast positive-parity sequences are proposed to be associated with the πg 7/2 configuration due to observations of several strong interband transitions, and two weakly populated I = 2 positive-parity bands are newly identified and interpreted as arising mainly from the πd 5/2 configuration. Three-quasiparticle configurations are assigned to the I π = 15/2 + and 23/2 + states according to the existing knowledge in neighboring nuclei; irregular noncollective and regular collective excitations built on these two (15/2 + and 23/2 + ) states are observed to coexist at similar energies. The observed three-quasiparticle band structures are further interpreted with the aid of configuration-constrained potential energy surface calculations.

The level scheme with spin up to I = 26 in the π [h 11/2 ]ν[i 13/2 ] yrast band in 162 Lu is reported and low-spin signature inversion with the inversion point at I = 20.5h is observed in this band. In the chain of Lu doubly-odd isotopes, with increasing neutron number, the low-spin staggering magnitude of signature dependence decreases and, at the same time, the inversion point shifts to lower spin.

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