Transition strengths and new band structures in odd-odd ⁷⁸Rb

High-spin states in ⁷⁸Rb were studied using the ⁵⁴Fe(²⁸Si,3pn) reaction at 120 MeV and the ⁵⁸Ni(²³Na,2pn) reaction at 65 and 70 MeV. Prompt and delayed γ-γ coincidences were measured using the Pitt-FSU detector array. Results from these experiments have led to new levels partly grouped into new bands, new spin-parity assignments, and a rearrangement of the low-lying portion of the level scheme. States were observed up to (19⁺) and (15^-) in the lowest energy positive- and negative-parity bands. Spin assignments were based on both directional correlation of oriented nuclei ratios and angular distributions. For some low-lying levels parity assignments were supported by a measurement of the linear polarizations of γ rays. Life-times were determined using the Doppler-shift attenuation method and direct timing. A reversal of signature splitting was observed in the yrast band at the 10⁺ state. Large alternations were seen in the B (M1) strengths in the yrast band, while the B(E2) values in the two most strongly populated bands show a considerable collective enhancement.