New high-spin level schemes and excitation modes of 117,118,119,120,122 Cd
New high-spin level schemes and excitation modes of 117,118,119,120,122 Cd
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DOI：
10.1016/j.nuclphysa.2011.11.001
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发表时间：
2012-01
期刊：
影响因子：
--
通讯作者：
J. Cole
中科院分区：
文献类型：
--
作者：
J. Cole
High-spin level schemes of {sup 117,118,119,120,122}Cd are expanded by analyzing our high-statistics triple and higher-fold coincidence events of prompt fission {gamma} rays from {sup 252}Cf at Gammasphere. Spin/parity assignments were made based on new {gamma}-{gamma} angular correlation measurements and level systematics in the neighboring isotopes. Stretch-aligned band structures observed in low-lying levels in {sup 117,119,121}Cd are seen to weaken with increasing spins, with a quasi-rotational degree of freedom manifested at higher spins. The{sup 5-}levels in even-N{sup 118,120}Cd were tentatively interpreted as candidates of quadrupole-octupole (QOC) coupling. The model-independent spin versus {h_bar}{omega} curves for even-N and odd-N Cd isotopes imply quasirotational alignment of an h11/2 neutron pair in the even-N Cd isotopes. The relative energies of the lowest 11/{sup 2-}, 9/{sup 2-}, 7/{sup 2-}, and 15/{sup 2-} levels in {sup 117}Cd and {sup 119}Cd 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).
High-spin level schemes of {sup 117,118,119,120,122}Cd are expanded by analyzing our high-statistics triple and higher-fold coincidence events of prompt fission {gamma} rays from {sup 252}Cf at Gammasphere. Spin/parity assignments were made based on new {gamma}-{gamma} angular correlation measurements and level systematics in the neighboring isotopes. Stretch-aligned band structures observed in low-lying levels in {sup 117,119,121}Cd are seen to weaken with increasing spins, with a quasi-rotational degree of freedom manifested at higher spins. The{sup 5-}levels in even-N{sup 118,120}Cd were tentatively interpreted as candidates of quadrupole-octupole (QOC) coupling. The model-independent spin versus {h_bar}{omega} curves for even-N and odd-N Cd isotopes imply quasirotational alignment of an h11/2 neutron pair in the even-N Cd isotopes. The relative energies of the lowest 11/{sup 2-}, 9/{sup 2-}, 7/{sup 2-}, and 15/{sup 2-} levels in {sup 117}Cd and {sup 119}Cd 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).