High-spin excitations of the odd-odd 8837Rb51 and 8635Br51 nuclei: πp3/2νd5/2 and πf5/2νd5/2 residual interactions

The odd-odd 8837Rb51 and 8635Br51 nuclei have been produced as fission fragments in the fusion reaction 18O+208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the triple γ-ray coincidence data and γ-γ angular correlations have been analyzed in order to assign spin and parity values to many observed states. The proposed configurations involve proton excitations from three sub-shells located close to the Fermi levels, πp3/2, πf5/2, and πg9/2, the νd5/2 neutron acting as a spectator. The residual πν interactions are extracted from the multiplets of states resulting from the πp3/2νd5/2 and πf5/2νd5/2 configurations. The empirical values of the latter are discussed and compared to those known in two similar configurations having jp=jn with lp=ln+1, where the role of the tensor force had been highlighted. (orig.)