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The high-spin states of the two neutron-rich nuclei 88Kr52 and 89Rb52 have been studied from the 18O+208Pb fusion-fission reaction. Their level schemes were built from triple β-ray coincidence data, and β-β angular correlations were analyzed in order to assign spin and parity values to most of the observed states. The two level schemes evolve from collective structures to single-particle excitations as a function of the excitation energy. Comparison with results of shell-model calculations gives the specific proton and neutron configurations which are involved to generate the angular momentum alongthe yrast lines. [ABSTRACT FROM AUTHOR]

The 83, 81As nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85 MeV bombarding energy and studied with the Euroball array. Medium-spin states of 83, 81As have been established up to ~3.5 MeV excitation energy. From angular correlation analysis, spin values have been assigned to most of the 81As excited states. The behaviors of the yrast structures identified in this work are discussed in comparison with the general features known in the mass région. Then they are compared to the results of two theoretical approaches: the "rotor + quasiparticle" for 81As and the shell model using the effective interactions JUN45 for 83, 81Ks. [ABSTRACT FROM AUTHOR]