Identification of levels in neutron-rich145Ceand147Cenuclei

Abstract

High-spin structures in the neutron-rich nuclei ${}^{145}\mathrm{Ce}$ and ${}^{147}\mathrm{Ce}$ produced in the spontaneous fission of ${}^{252}\mathrm{Cf}$ have been investigated by prompt $\ensuremath{\gamma}$-ray spectroscopy. A collective band structure in ${}^{145}\mathrm{Ce}$ is identified. Several sidebands along with the new high-spin states in ${}^{147}\mathrm{Ce}$ are also identified. Particle-plus-rotor model calculations indicate that the yrast bands in ${}^{145}\mathrm{Ce}$ and ${}^{147}\mathrm{Ce}$ most probably originate from coupling of the $\ensuremath{\nu}{i}_{13/2}$ orbital to the ground states of ${}^{144}\mathrm{Ce}$ and ${}^{146}\mathrm{Ce}.$ The ground state configurations of ${}^{145,147}\mathrm{Ce}$ are $(\ensuremath{\nu}{h}_{9/2}+\ensuremath{\nu}{f}_{7/2})$ and $\ensuremath{\nu}{h}_{9/2},$ respectively.