Nuclear structure studies in the mass-90 region with the (³He, d) reaction

Abstract

The (³He,d) reaction on target nuclei of ⁹⁰Zr, ⁹¹Zr, ⁹²Zr and ⁹³Nb was studied using 31-MeV ³He ions from the Oak Ridge Isochronous Cyclotron. The deuteron groups corresponding to low-lying excited states in the residual nuclei, ⁹¹Nb, ⁹²Nb, ⁹³Nb and ⁹⁴Mo, were recorded in a broad-range magnetic spectrograph. Angular distributions for these states were compared with distorted-wave calculations to obtain angular momentum transfers and spectroscopic factors. The shell-model configurations of the protons in the nuclei studied were inferred from the spectroscopic information and model systematics. Shell-model functions, based on an assumed ⁸⁸Sr core and inferred two-body residual interactions among the extra-core nucleons, were tested by comparison with spectroscopic results. In particular, overlap integrals and predicted excitation energies were compared with spectroscopic factors and experimental excitation energies. Evidence for proton holes in the 2p[subscript 3/2] orbital was shown for each target, and the distribution of protons among the lf[subscript 5/3], 2p[subscript 3/2] and lg[subscript 9/2] orbitals was inferred for each target.