Identification of levels in neutron-rich {sup 145}Ce and {sup 147}Ce nuclei

High-spin structures in the neutron-rich nuclei {sup 145}Ce and {sup 147}Ce produced in the spontaneous fission of {sup 252}Cf have been investigated by prompt {gamma}-ray spectroscopy. A collective band structure in {sup 145}Ce is identified. Several sidebands along with the new high-spin states in {sup 147}Ce are also identified. Particle-plus-rotor model calculations indicate that the yrast bands in {sup 145}Ce and {sup 147}Ce most probably originate from coupling of the {nu}i{sub 13/2} orbital to the ground states of {sup 144}Ce and {sup 146}Ce. The ground state configurations of {sup 145,147}Ce are ({nu}h{sub 9/2}+{nu}f{sub 7/2}) and {nu}h{sub 9/2}, respectively. (c) 1999 The American Physical Society.