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Abstract: 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 levels in even-N 118,120Cd were tentatively interpreted as candidates of quadrupole–octupole (QOC) coupling. The model-independent spin versus ℏω curves for even-N and odd-N Cd isotopes imply quasi-rotational alignment of an neutron pair in the even-N Cd isotopes. The relative energies of the lowest , , , and 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). [Copyright &y& Elsevier]

Abstract: The level scheme of odd-Z neutron-rich 141Cs (, ) was extended and expanded and that of 144Cs () was identified for the first time by means of coincidence measurements of prompt γ rays in the spontaneous fission of 252Cf with Gammasphere. Spin/parity was assigned to the levels based on angular correlations and level systematics in 141,143Cs. Parity doublets characteristic of both simplex quantum number and were proposed in 141Cs. The tests by using rotational frequency ratio imply octupole vibrations in 141Cs and 143Cs. values and electric dipole moments were calculated for 141Cs, and re-determined for 143Cs. It was found that values of 141Cs are simplex-dependent and the average value is one order of magnitude larger than that of 143Cs, and the deduced dipole moment of 141Cs is considerably larger than that of 143Cs, and comparable to the isotone 142Ba. For 144Cs the yrast sequence looks like a well-deformed rotational band, but no octupole band structure was identified in this nucleus. The overall variations of in 141,143,144Cs exhibit a pronounced drop of dipole moment with increasing neutron number in this odd-Z isotopic chain, which may be analogous in nature to the quenching of observed in even–even 146Ba (, ) and 224Ra (, ), and to the drop of in the odd-Z neutron-rich 147La (, ) reported by our collaboration. [Copyright &y& Elsevier]

Abstract: The yrast and near-yrast level scheme of light neutron-rich 143La (, ) is reinvestigated and expanded and that of 144La () is proposed for the first time by measuring prompt γ rays from the spontaneous fission of 252Cf at Gammasphere. Spins/parities are assigned to the lowest-lying levels of 143,144La based on the early studies of decay, and the assignments for high-spin levels of 143,144La are made by measuring internal conversion coefficients and following the level systematics of the neighboring heavier La isotopes and even–even Ba and Ce nuclei. The ratios, energy displacements and rotational frequency ratios of the new parity-doublets of 143,144La indicate that octupole deformations/correlations also develop in these nuclei. The band-crossings observed in a rotational frequency range of 0.31 to 0.34 MeV for the two even-parity bands in 143La but being absent in 144La are interpreted as due to alignment of a pair of neutrons in 143La. [Copyright &y& Elsevier]