Abstract
The low-spin structure of the semimagic nucleus has been considerably expanded: combining four experiments, several and excited states were identified below 4.5 MeV, and their properties established. The Monte Carlo shell model accounts for the results and unveils an unexpectedly complex landscape of coexisting shapes: a prolate excitation is located at a surprisingly high energy (3463 keV), with a collective state 286 keV above it, the first such observation in Ni isotopes. The evolution in excitation energy of the prolate minimum across the neutron subshell gap highlights the impact of the monopole interaction and its variation in strength with .
- Received 24 June 2020
- Accepted 31 July 2020
DOI:https://doi.org/10.1103/PhysRevLett.125.102502
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society