Magnetic rotation in 82Rb and 84Rb

High-spin states in 82Rb and 84Rb were populated in the reaction 11B + 76Ge at beam energies of 45 and 50 MeV. Gamma rays were detected with the spectrometer GASP. The level schemes of 82Rb and 84Rb were extended up to 6.0 and 7.4 MeV, respectively. Mean lifetimes of five levels in 82Rb and eleven levels in 84Rb were determined using the Doppler-shift-attenuation method. Regular magnetic dipole bands including strong M1 and weak E2 transitions observed in both nuclei show the characteristic features of magnetic rotation. These bands have been successfully described in the tilted-axis cranking model on the basis of the four-quasiparticle configuration pi(fp) pi(g_{9/2}^2) \nu(g_{9/2}). The calculations reproduce the band-like properties as well as absolute B(M1) and B(E2) transition strengths in both nuclei, which supports the concept of
magnetic rotation. Excited states in 84Rb were also interpreted in terms of the shell model using the model space
pi(0f_{5/2},1p_{3/2},1p_{1/2},0g_{9/2}) nu(1p_{1/2},0g_{9/2}).
These calculations reproduce the low-spin states. Moreover, calculated states with the main configuration
pi(0f_{5/2}^{-2}1p_{3/2}^{-1} 0g_{9/2}^2) nu(0g_{9/2}^{-3}) can be combined to M1 sequences that reproduce roughly
the experimental transition strengths, but do not describe the features of magnetic rotation, as regular level spacings and B(M1) values decreasing with increasing rotational frequency.