Excited states and reduced transition probabilities in Os 168

Abstract

The level scheme of the neutron-deficient nuclide Os168 has been extended and mean lifetimes of excited states have been measured by the recoil distance Doppler-shift method using the JUROGAM γ-ray spectrometer in conjunction with the IKP Köln plunger device. The Os168γ rays were measured in delayed coincidence with recoiling fusion-evaporation residues detected at the focal plane of the RITU gas-filled separator. The ratio of reduced transition probabilities B(E2;41+→21+)/B(E2;21+→01+) is measured to be 0.34(18), which is very unusual for collective band structures and cannot be reproduced by interacting boson model (IBM-2) calculations based on the SkM∗ energy-density functional.