Multi-quasiparticle states and K-forbidden transitions in 183Os Original Research Article

High-spin states in 183Os have been studied using the 170Er(18O, 5n) reaction at a beam energy of 85 MeV. Nine rotational bands based on 1-, 3-, 5- and 7-quasiparticle excitations have been observed. Nilsson configurations are assigned for the newly observed bands using g-factors deduced from M1/E2 branching ratios within the bands. In addition, two isomers with Kπ=(43/2+) and (43/2−) have been identified. The Kπ=(43/2+) isomer decays directly to the Kπ=9/2+ ground-state band with a large difference in the K quantum number, ΔK=17. The decay rates are discussed in terms of a tunneling model where high-K (isomeric) and low-K states interact via fluctuations towards triaxial nuclear shapes.