Single-particle and collective excitations in the N=28 isotones Fe 54 and Mn 53

D. Rudolph, I. Ragnarsson, C. Andreoiu, M. A. Bentley, M. P. Carpenter, R. J. Charity, R. M. Clark, J. Ekman, C. Fahlander, P. Fallon, W. Reviol, D. G. Sarantites, D. Seweryniak

Research output: Contribution to journalArticlepeer-review

Abstract

The fusion-evaporation reaction S32+Si28 at 125 MeV beam energy was used to populate high-spin states in the semimagic N=28 nuclei Mn53 and Fe54. With a combination of the Gammasphere spectrometer and ancillary devices including the Microball CsI(Tl) array, extensive high-spin level schemes are derived. They exhibit rotational-like collective structures and competing single-particle excitations. The experimental results are compared with predictions from shell-model calculations, for which the inclusion of isopin-symmetry-breaking terms is found to improve the description. An interpretation of the high-spin states is put forward using cranked Nilsson-Strutinsky calculations, indicative of contributions from collective excitations beyond some 8-MeV excitation energy and highlighting the importance of the g9/2 intruder orbital in this energy range.

Original languageEnglish
Article number014316
Number of pages27
JournalPhysical Review C
Volume102
Issue number1
DOIs
Publication statusPublished - 21 Jul 2020

Bibliographical note

Funding Information:
We would like to thank the accelerator crews and the Gammasphere support staff at Argonne and Berkeley for their supreme efforts. This research used resources of ANL's ATLAS facility, which is a DOE Office of Science User Facility. This work is supported in part by the Swedish Research Council (Vetenskapsrådet, VR 2016-3969) and the U.S. Department of Energy under Grants No. DE-AC02-05CH11231 (LBNL), No. DE-AC02-06CH11357 (ANL), and No. DE-FG05-88ER-40406 (WU).

Publisher Copyright:
© 2020 authors. Published by the American Physical Society.

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