High-spin states in Lu-171

Rotational bands in the odd-proton nucleus Lu-171 have been populated with the Gd-160(F-19, alpha 4n) reaction. High-spin states were observed to a ma ximum spin of 73/2(-) using the NORDBALL array. Several new three-quasipart icle bands were observed, including one based on the pi 1/2(-) [541]x nu 7/ 2(+) [633]x nu 1/2(-) [521] configuration. The signature splitting of this band is inverted from the expected splitting, and this is interpreted as be ing 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 pi 1/2(-) [541] band is considered. Strong E1 tr ansitions from high-spin levels in the pi 1/2(+) [411] band to the pi 1/2(- ) [541] band are observed. (C) 1998 Elsevier Science B.V.