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

Shell Structures in 91 Nb

“…In this mass region, the shapes of nuclei in the neighborhood of zirconium with 𝑁 < 44 tend toward a permanent ground-state deformation, while with neutron number increasing, approaching to closed shell at 𝑁 = 50, the collective properties are diminished, then the nuclei with 𝑁 > 44 show more like weakly deformed or spherical vibrators behavior. The high spin structures in niobium isotopes are good examples to show this tendency, i.e., 83,84,85,86 Nb [1−4] were observed to have clear rotational structures, whereas in 87 Nb [5] and 88 Nb [6] they exhibit few-particle excitations at the low spin states and collective rotation at the high spin states, furthermore in 89 Nb, [7] intrinsic excitation dominates its level structures. In this Letter, we investigate the structures at high angular momentum in the Nb isotopes, 90,91 Nb, towards the vicinity of 𝑁 = 50 shell closure.…”

“…Here we report the preliminary experimental results on 91 Nb. The 91 Nb nucleus has been investigated before using light beams, like alpha and 6 Li, for the spectroscopic study. [9,10] Thus, only relatively low spin states are known in this nucleus.…”