High-spin states and intrinsic structure in 174Os and 175Os: Alignments and strong interaction

Abstract

Abstract High-spin states have been identified in 174Os and 175Os using (HI, x>n) reactions and gamma-ray techniques. Rotational bands built on low-lying intrinsic states in 175Os have been observed for the first time. The intrinsic states are identified as a mixed i 13 2 neutron state (nominally 7 2 + [633] ) and the 1 2 − [521] and 5 2 − [512] Nilsson configurations. Differences in the alignment of the two signatures of the decoupled band built on the 1 2 − [521] state and the comparison between the signature splitting of routhians and if B(M1)/B(E2) values in the i 13 2 band suggest softness towards gamma deformation. Crossing transitions between the negative-parity bands at intermediate spin have been observed and the interaction strength derived from the branching ratios. A comparison of the properties of bands in 174Os and 175Os shows some expected similarities, but also surprising differences which point towards the need for a more comprehensive treatment in strong interaction cases. Depending on the choice of reference the alignment in the i l3 2 band might show degenerate BC and AD crossings at a relatively low frequency. This may be consistent with the alignment observed in the negative parity side bands in 174Os.