Very neutron-rich Z ∼ 60 isotopes produced by in-flight fission of 345 MeV/nucleon 238 U beam at the RI Beam Factory, RIKEN Nishina Center have been studied by delayed γ-ray spectroscopy. New isomers are discovered in the neutron-rich N = 100 isotones, 162 Sm, 163 Eu, and 164 Gd. Half-lives, γ-ray energies and relative intensities of these isomers were obtained. Level schemes were proposed for these nuclei and the first 2 + and 4 + states were assigned for the even-even nuclei. configurations with similar excitation energy. The results suggest that neutron-rich N = 100 nuclei are well deformed and the deformation gets larger as Z decreases to 62. The onset of K isomers with the same configuration at almost the same energy in N = 100 isotones indicates that the neutron single-particle structures of neutron-rich isotones down to Z = 62 do not change significantly from those of the Z = 70 stable nuclei. Systematics of the excitation energies of new isomers can be explained without the predicted N = 100 shell gap.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.