NEW ISLAND OF MU-S ISOMERS IN NEUTRON-RICH NUCLEI AROUND THE Z = 28 AND N = 40 SHELL CLOSURES

New isomeric states in the neutron-rich nuclei near the Z = 28 and N = 40 shell closures have been identified among the reaction products of a 60.3A MeV Kr-86 beam on a Ni-nat target. From the measured isomeric decay properties information about the excited states and their nucle ar structure has been obtained. The isomerism is related mostly to the occupation of the neutron g(9/2) orbital, an intruder level in the N = 3 fp shell. It is illustrated with the decay properties of Ni-69(m), Ni-70(m), and Cu-71(m) interpreted within the nuclear shell model. [S 0031-9007(98)06719-2].