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The odd-odd 88 37Rb51 and 86 35Br51 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 $ \gamma$ -ray coincidence data and $ \gamma$ - $ \gamma$ 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, $ \pi$ p3/2 , $ \pi$ f5/2 , and $ \pi$ g9/2 , the $ \nu$ d5/2 neutron acting as a spectator. The residual $ \pi$ $ \nu$ interactions are extracted from the multiplets of states resulting from the $ \pi$ p3/2 $ \nu$ d5/2 and $ \pi$ f5/2 $ \nu$ d5/2 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. [ABSTRACT FROM AUTHOR]

The 81, 82, 83, 85Se 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 $ \gamma$ -ray coincidence data and $ \gamma$ - $ \gamma$ angular correlations have been analyzed in order to assign spin and parity values to many observed states. The lowest-spin states of the two-neutron and three-neutron configurations are strongly mixed with two-proton excitations among the fp orbits. On the other hand, the highest-spin states of these neutron configurations are found to remain almost pure. Neutron excitation across the N = 50 gap is observed both in 83Se49 and in 85Se51 . [ABSTRACT FROM AUTHOR]

The 84, 85Br nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. The high-spin states of the odd-odd 84Br nucleus have been identified for the first time, the observed structure being built on the known 6- isomeric state. High-spin states of 85Br have been observed up to 5.4MeV excitation energy and spin I ∼ 21/2. From angular correlation analysis, spin values have been assigned to most of the 85Br excited states up to 4MeV. None of these excited states has been found to exhibit a delayed decay having T 1/2 > 10ns. All the observed states in 84, 85Br can be described by various proton excitations involving at least the two sub-shells ( π f 5/2 and π p 3/2) located just above the Z = 28 shell closure. [ABSTRACT FROM AUTHOR]

The 87Kr nucleus has been produced as fission fragment in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. High-spin states of this neutron-rich isotope have been identified for the first time. Its level scheme has been obtained up to 6.3MeV excitation energy and spin I ∼ 23/2ℏ. Its structure is interpreted by analogy with those of the heavier isotones. The proposed configurations involve both proton and neutron excitations from several sub-shells located close to the Fermi levels, particularly ν d 5/2, π p 3/2 f 5/2 and π g 9/2. Moreover, a revised spin value of 5/2- for the 87Br ground state is proposed. [ABSTRACT FROM AUTHOR]

The121,123,125,127Sb nuclei have been produced as fission fragments in three reactions induced by heavy ions:12C +238U at 90 MeV bombarding energy,18O +208Pb at 85 MeV, and31P +176Yb at 152 MeV. Their level schemes have been built from gamma rays detected using the EUROBALL III and IV arrays. High-spin states of123,125,127Sb nuclei have been identified for the first time. Moreover isomeric states lying around 2.3 MeV have been established in123,125,127Sb from the delayed coincidences between the fission fragment detector SAPhIR and the gamma array. All the observed states can be described by coupling ad5/2 org7/2 proton to an excited Sn core involving either vibrational states or broken neutron pairs. [ABSTRACT FROM AUTHOR]

The84Se nucleus has been produced as fission fragment in the fusion reaction18O +208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Medium-spin states of this neutron-rich isotope have been identified for the first time. Its level scheme has been obtained up to 4.9MeV excitation energy and spinI~ 7?. Its structure is interpreted by analogy with those of the stable heavier isotones. The evolution of the energy of theN= 50 neutron-core excitation is discussed as a function of the proton number. [ABSTRACT FROM AUTHOR]

The 104,106,108Ru nuclei have been produced as fission fragments following the fusion reaction 28Si + 176Yb at 145 MeV bombarding energy; prompt gamma rays emitted in the reaction were detected using the Eurogam II array. Their high-spin level schemes have been obtained, particularly several side bands have been extended or newly observed. Experimental results are discussed in the framework of both collective model and the rotating mean-field approach in which the Gogny force is the sole input. These calculations provide very good descriptions of both low-spin and high-spin structures observed in the neutron-rich even- A Ru isotopes. [ABSTRACT FROM AUTHOR]