Observation of a (ν72−[514])2 crossing in 180Os

High-spin states in 180Os have been populated by means of the 150Nd(36S,6n) reaction at 177 MeV and studied with the γ-spectrometers OSIRIS and GASP. Eight known bands have been extended to higher spins and a new strongly coupled band has been discovered. Configuration assignments of the bands have been carried out in the framework of the tilted-axis cranking model utilizing experimental ratios of reduced transition probabilities B(M1)B(E2). The investigation of the alignment behaviour of the bands revealed that besides the well-known first band crossing caused by the alignment of an i132 quasineutron pair, a second band crossing occurs in four of the bands. The crossing frequency is ⩾ 0.38 MeV and the alignment gain is fairly small, ranging between 2 and ⩾4 ℏ;. The crossing can consistently be explained as a two-quasineutron (ν72−[514])2 alignment. This crossing has been observed for the first time.