Structure of \(^{83}\)As, \(^{85}\)As and \(^{87}\)As: from semi-magicity to \(\gamma\)-softness

• Published in: arXiv.org
• Main Authors: Rezynkina, K, Dao, D D, Duchene, G, Dudouet, J, Nowacki, F, Clement, E, Lemasson, A, Andreoiu, C, Astier, A, de Angelis, G, de France, G, Delafosse, C, Deloncle, I, Didierjean, F, Dombradi, Z, Ducoin, C, Gadea, A, Gottardo, A, Guinet, D, Jacquot, B, Jones, P, Konstantinopoulos, T, Kuti, I, Korichi, A, Lenzi, S M, G Li, F Le Blanc, Lizarazo, C, Lozeva, R, Maquart, G, Million, B, Michelagnoli, C, Napoli, D R, Navin, A, Perez-Vidal, R M, Petrache, C M, Pietralla, N, Ralet, D, Ramdhane, M, Rejmund, M, Stezowski, O, Schmitt, C, Sohler, D, Verney, D
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 18.03.2022
• Subjects: Atomic properties; Gamma rays; Protons; Softness
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2203.10108

The structure of \(^{83}\)As, \(^{85}\)As and \(^{87}\)As have been studied in fusion-fission reaction \(^{238}\)U+\(^9\)Be. Fission fragments were identified in mass and atomic number using the VAMOS++ spectrometer and the coincident \(\gamma\)-rays were detected in the \(\gamma\)-ray tracking array AGATA. New transitions in \(^{83}\)As and \(^{85}\)As are reported and placed in the level schemes. A level scheme of the excited states in \(^{87}\)As is proposed for the first time. The data are interpreted in frame of Large-Scale Shell-Model calculations, SU3 symmetries and Beyond Mean-Field frameworks. A spherical regime at magic number \(N\)=50 is predicted and the location of the proton \(g_{9/2}\) orbital is proposed for the first time. Development of collectivity in a prolate deformed, \(\gamma\)-soft regime in the open shell cases \(^{85}\)As and \(^{87}\)As, most neutron-rich isotopes beyond \(N\)=50, is concluded. Data and theoretical calculations give confidence to a relatively high extrapolated excitation energy about 4 MeV of the \(9/2^+\) state in \(^{79}\)Cu, one proton above \(^{78}\)Ni.