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

High-spin states in Nb92 have been investigated by using in-beam γ ray spectroscopy with the Se82(N14,4n)Nb92 reaction at a beam energy of 54 MeV. The positive-parity decay sequences above the previously known state 13+ have been extended to Iπ≥(20+) by adding nineteen new γ rays. The level structures in Nb92 have been interpreted in terms of the shell model calculations performed in the configuration space π(1f5/2,2p3/2,2p1/2,1g9/2) for the protons and ν(2p1/2,1g9/2,1g7/2,2d5/2) 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≈(18-20) with excitation energies above 8.5 MeV.