SPECTROSCOPY OF RU-96-98 AND NEIGHBORING NUCLEI - SHELL-MODEL CALCULATIONS AND LIFETIME MEASUREMENTS

High Spin states in Mo-94,Mo-95, Tc94-96, Ru96-98 and Rh-97,Rh-98 were populated via the Cu-65(S-36,xpyn) reactions at 142 MeV. Level scheme s of these nuclei have been extended up to a spill of J approximate to 20HBAR and an excitation energy of E(x) approximate to 12-14 MeV. Inf ormation on the high spin structure for Tc-96 and Rh-95 has been obtai ned for the first time. Spherical shell model calculations have been p erformed and compared with the experimental excitation energies. The l evel structures of the N = 51, 52 isotones exhibit single-particle nat ure even at the highest spins and excitation energies. A fragmentation of intensity into several branches after breaking of the N = 50 core has been observed. There are indications for the onset of collectivity around neutron number N = 53 in this mass region. A sequence of E2 tr ansitions, reminiscent of vibrational degree of freedom, were observed in Ru-98 at spins just above the observed N = 50 core breaking. RDM l ifetime measurements have been performed to ascertain the intrinsic st ructures of these level sequences.