High-Kstates in the odd-odd nuclideRe180

Abstract

The structure of the deformed, doubly odd nuclide 180 Re has been studied by γ -ray and conversion-electron spectroscopy using the 174 Yb( 11 B,5n) reaction with a pulsed 71 MeV beam of 11 B ions. Several of the previously known intrinsic states have been given revised spin and parity assignments. Rotational bands are observed with K π = (4 + ), (5 − ), (7 + ), 8 + , 9 − , 13 + , 14 − , 15 − , 16 + , 21 − , and (22 + ). Among these, a four-quasiparticle t band is identified, which is already energetically favored at its bandhead compared to the corresponding two-quasiparticle band; and two six-quasiparticle bands are identified and associated with a τ = 13 µs isomer. The observed structures, including g factors and alignments, are interpreted with the aid of Nilsson-plus-BCS calculations and configuration-constrained potential energy surface calculations. Reduced-hindrance values are obtained for K-forbidden transitions, illustrating the important role of the K quantum number for near-yrast isomers.

High-spin states in odd-odd174Re

“…Band 3 is, hence, interpreted as a four-quasiparticle band. Considering the active quasiparticle orbitals, two candidates for a four-quasiparticle band with K π = 14 − are π 9/2 − [ [46,49], with K eff = 16.96 and a bandhead energy E = 1755 keV. That band was described as π 9/2 − [514] ⊗ ν5/2 − [512], 7/2 − [514], 9/2 + [624], K π =15 − .…”

γ -ray spectroscopy of a four-quasiparticle isomer band in Re174

“…The present work is concerned with an odd-odd, neutrondeficient isotope of rhenium, 174 75 Re 99 . Until recently, the lightest odd-odd rhenium isotope observed with a multiquasiparticle isomer was 180 Re [1,3], but Guo et al [4] have reported evidence for the existence of a strongly populated, four-quasiparticle isomer in 174 Re, with a half-life exceeding 1 μs. In this work, a new study of 174 Re is presented.…”