New high-spin level schemes and excitation modes of 117,118,119,120,122Cd

Journal article

High-spin level schemes of 117,118,119,120,122Cd are expanded by analyzing our high-statistics triple- and higher-fold coincidence events of prompt fission γ rays from 252Cf at Gammasphere. Spin/parity assignments were made based on new γ-γ angular correlation measurements and level systematics in the neighboring isotopes. Stretch-aligned band structures observed in low-lying levels in 117,119,121Cd are seen to weaken with increasing spins, with a quasi-rotational degree of freedom manifested at higher spins. The 5 - levels in even-N 118,120Cd were tentatively interpreted as candidates of quadrupole-octupole (QOC) coupling. The model-independent spin versus h{stroke}ω curves for even-N and odd-N Cd isotopes imply quasi-rotational alignment of an h 11/2 neutron pair in the even-N Cd isotopes. The relative energies of the lowest 11/2 -, 9/2 -, 7/2 -, and 15/2 - levels in 117Cd and 119Cd suggest triaxial shapes based on Meyer-Ter-Vehn theory for these odd-N Cd nuclei. For the even-N Cd isotopes evidence of triaxiality may also be provided by the Shell Correction version of the Tilted Axis Cranking model (SCTAC). © 2011 Elsevier B.V.

Authors: Luo, Y; Rasmussen, J; Nelson, C; Hamilton, J; Ramayya, A

• Publication status: Published
• Journal: NUCLEAR PHYSICS A
• Volume: 874
• Pages: 32-61
• Publication date: 2012-01-15
• DOI: 10.1016/j.nuclphysa.2011.11.001
• ISSN: 0375-9474
• Language: English
• Keywords: RADIOACTIVITY Cf-252(SF); measured E-gamma, I-gamma, gamma gamma gamma-coin, angular correlations using the Gammasphere array.Cd-117,Cd-118,Cd-119,Cd-120,Cd-122; deduced levels. J, pi, quasi-rotational bands, configurations, B(E1)/B(E2) ratios. Comparison with various models and total Routhian surface calculations. Triaxiality