Isomer spectroscopy of neutron rich 190W116

Abstract Gamma-rays de-exciting a millisecond isomer in the neutron-rich nucleus 190 74 W 116 have been observed following relativistic projectile fragmentation of a 1 GeV per nucleon 208 Pb beam. The isomeric decay populates the ground-state rotational band, with energies that indicate a significant deformation change at Z =74 for the N =116 isotones. The successful application of the projectile fragmentation technique in a region of deformed nuclei opens up the prospect of exploiting K -isomer decays to probe the evolution of collective nuclear structure far from the valley of beta stability.