In-beam study of 78Br

Abstract High-spin states in 78 Br decaying into the 4 + isomer at 180.8 keV were excited via the 77 Se(α, 2np) and 76 Ge ( 7 Li, 5n) reactions. A sequence of closely lying levels with I ⩽ 8 is found between 227.6 and 467.6 keV. The highest state in this group is populated by a relatively strong 904.1 keV ΔI = 2 transition. These features provide a basis for a comparison with the positive-parity ground-state Coriolis-distorted band of 79 Kr, in the light of a rotor plus one- and two-quasiparticle descriptions. Other previously reported low-spin states are also seen weakly with this reaction. Two new isomeric states of 9±1 ns at 337.8 keV and 84±8 ns at 227.6 keV are found. The latter decays into the 4 + isomer through a 46.8 keV transition, which lies unresolved from the 46.3 keV line. The existence of this doublet explains an earlier discrepancy.