Reinvestigation of the high-spin level structure of Nb 92 : Excitations across the Z = 38 and N = 50 closed shells

High-spin states in Nb-92 have been investigated by using in-beam gamma ray spectroscopy with the Se-82(N-14, 4n)Nb-92 reaction at a beam energy of 54 MeV. The positive-parity decay sequences above the previously known state 13(+) have been extended to I-pi >= (20(+)) by adding nineteen new gamma rays. The level structures in Nb-92 have been interpreted in terms of the shell model calculations performed in the configuration space pi(1f(5/2), 2p(3/2), 2p(1/2), 1g(9/2)) for the protons and nu(2p(1/2), 1g(9/2), 1g(7/2), 2d(5/2)) for the neutrons. The calculated results show that the inclusion of proton core excitation relative to the Z = 38 subshell closure and neutron particle-hole excitation for the N = 50 shell closure are essential to adequately describe the experimental high-spin states at I approximate to (18-20)h with excitation energies above 8.5 MeV.