Single-particle states and parity doublets in odd- Z Ac 221 and Pa 225 from α -decay spectroscopy

E. Parr, J. F. Smith, P. T. Greenlees, P. A. Butler, K. Auranen, R. Chapman, D. M. Cox, D. M. Cullen, L. P. Gaffney, T. Grahn, E. T. Gregor, L. Grocutt, A. Herzáň, R. D. Herzberg, D. Hodge, U. Jakobsson, R. Julin, S. Juutinen, J. M. Keatings, J. KonkiM. Leino, P. P. McKee, C. McPeake, D. Mengoni, A. K. Mistry, B. S.Nara Singh, G. G. O'Neill, J. Pakarinen, P. Papadakis, J. Partanen, P. Peura, P. Rahkila, P. Ruotsalainen, M. Sandzelius, J. Sarén, M. Scheck, C. Scholey, M. Siciliano, M. Smolen, J. Sorri, P. Spagnoletti, K. M. Spohr, S. Stolze, M. J. Taylor, J. Uusitalo

Research output: Contribution to journalArticlepeer-review


Low-lying states in the odd-Z isotopes Ac13289221 and Pa13491225 have been studied using α-particle and αγ-coincidence spectroscopy in the Pa225→Ac221→Fr217 decay chain. Ground-state spin and parity assignments of Iπ = 5/2- are proposed for both Ac221 and Pa225, with the odd proton occupying the ω = 5/2 orbital of the quadrupole-octupole deformed shell model in both nuclei. In Ac221, excited states in the bands based on the ω = 5/2 and ω = 3/2 orbitals have been identified, including proposed parity-doublet states. The results suggest that reflection-asymmetric deformation of the ground state persists in the odd-A members of the isotope chains down to N = 132 for Ac and N = 134 for Pa, before reaching the transitional region at N = 130.

Original languageEnglish
Article number034303
JournalPhysical Review C
Issue number3
Publication statusPublished - 2022 Mar

Subject classification (UKÄ)

  • Subatomic Physics


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