Excited states in91Nb populated in the89Y(α, 2nγ) reaction

The reaction⁸⁹Y(α, 2n γ) was used to populate excited states in⁹¹Nb. The de-excitation of these states was studied by in-beam gamma-ray spectroscopy, involving the measurement of excitation functions, angular distributions and life-times. A 17/2^? isomeric state at 2034 keV and withT _1/2=3.8±0.2 μs was observed; it is interpreted as the highest-spin state of the {(g _9/2)² (p _1/2)} proton configuration. The experimental results are compared with other published data and with shell-model calculations.