Multiparticle-hole states of high spin in N < 50, A ≈ 90 nuclei: 3. The odd-odd nucleus 88Nb

Abstract

High spin states in the nucleus Tc-89 have been studied via the fusion evaporation reaction Ni-58(Ca-40,2 alpha p)Tc-89 at 180 MeV beam energy. The NORDBALL gamma-ray spectrometer equipped with auxiliary detectors for light particle selection was used to measure gamma gamma- and particle-gamma gamma coincidences. Some 60 transitions were placed into a level scheme comprising 38 levels reaching up to 9.2 MeV excitation energy and a possible spin of I = 45/2HBAR The level scheme is compared to those of neighbouring nuclei and interpreted in terms of the spherical shell model. The calculations were performed with different sets of parameters within a restricted pi(p(1/2)), pi(g(9/2)), nu(p(1/2)) and nu(g(9/2)) configuration space. States above 2.3 MeV excitation energy are well reproduced by shell model calculations based on an empirical residual interaction, whereas collective excitations are suggested to contribute to the wave functions of lower lying states. (Less)