Gamma-ray spectroscopy of 79Rb and 81Sr

High spin states in 79Rb and 81Sr were populated through the bombardment of a 58Ni target with a 30Si beam at 134 MeV. Gamma rays depopulating the excited states were detected using the EUROGAM phase-2 array. A band of nine transitions has been observed in 81Sr decaying to the α=-1/2 sequence built on the [303]5/2- Nilsson orbit. The decay schemes of several bands in both 79Rb and 81Sr have been extended to higher spin with angular correlation measurements providing firm spin assignments for a number of states. A fork is observed in 79Rb after a band crossing at ℎω≅0.72 MeV in the α=+1/2 sequence built on the [312]3/2- Nilsson orbit. A previously observed cascade of three γ-rays in 79Rb has been extended by the addition of ten transitions up to 16 MeV. This has been assigned as a positive parity band built on the [440]1/2+ Nilsson orbit. (orig.)