High-spin states in 171Lu

Abstract Rotational bands in the odd-proton nucleus 171 Lu have been populated with the 160 Gd( 19 F, α4n) reaction. High-spin states were observed to a maximum spin of 73 2 − using the NORD-BALL array. Several new three-quasiparticle bands were observed, including one based on the π 1 2 − [541]⊗ν 7 2 + [633]⊗ν 1 2 − [521] configuration. The signature splitting of this band is inverted from the expected splitting, and this is interpreted as being due to a residual proton-neutron interaction. The contribution of this interaction to the increased crossing frequency observed for the alignment of i 13 2 neutrons in the π 1 2 − [541] band is considered. Strong E1 transitions from high-spin levels in the π 1 2 + [411] band to the π 1 2 − [541] band are observed.