Abstract
Background: Shell evolution can impact the structure of the nuclei and lead to effects such as shape coexistence. The nuclei around represent an excellent study case, however, spectroscopic information of the neutron-rich, nuclei is limited.
Purpose: The goal is to measure -ray transitions in , and populated in the decay of to determine absolute feedings and relative -decay probabilities and to compare the results with Monte Carlo shell model calculations in order to study the influence of the relevant single neutron and proton orbital occupancies around and .
Method: The low-energy structures of , and were studied in the decay of produced at ISOLDE, CERN. The beam was purified by means of laser resonance ionization and mass separation. The and events detected by three plastic scintillators and two MiniBall cluster germanium detectors, respectively, were correlated in time to build the low-energy excitation schemes and to determine the -decay half-lives of the nuclei.
Results: The relative small -decay ground state feeding of obtained in this work is at variant to the earlier studies. Spin and parity was assigned to the ground state based on the strong ground-state feeding in the decay of as well as in the decay of . Experimental log() values, -ray de-excitation patterns, and energies of excited states were compared to Monte Carlo shell model calculations. Based on this comparison, spin and parity assignments for the selected number of low-lying states in the to chain were proposed.
Conclusions: The -decay chain starting toward , crossing , evolves from deformed nuclei to sphericity. The -decay population of a selected number of and states in , which is understood within shape coexistence framework of Monte Carlo shell model calculations, reveals the crucial role of the neutron shell and proton excitations across the gap.
15 More- Received 2 August 2018
- Revised 14 October 2018
DOI:https://doi.org/10.1103/PhysRevC.98.064326
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