Study of medium-spin states of neutron-rich

Excited states of the rubidium isotopes 37 87, 89, 91Rb have been studied at the INFN Legnaro National Laboratory. Measurements of the $\gamma$-ray decay of fragments produced in binary grazing reactions resulting from the interaction of a beam of 530 MeV 96Zr ions with a 124Sn target have been complemented by studies of the $\gamma$-ray decay of fission fragments produced in the interaction of a beam of 230 MeV 36S ions with a thick 176Yb target. The structure of the yrast states of 37 87, 89, 91Rb has been discussed within the context of spherical shell-model and cranked Nilsson-Strutinsky calculations