1. Structure of $^{83}$As, $^{85}$As and $^{87}$As: from semi-magicity to $\gamma$-softness
- Author
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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., Li, G., Blanc, F. Le, 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., and Verney, D.
- Subjects
Nuclear Experiment - Abstract
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.
- Published
- 2022
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