Octupole correlations in neutron-rich {sup 145,147}La nuclei: Coriolis-limit-coupling bands with aligned h{sub 11/2} proton
- Physics Department, Tsinghua University, Beijing 100084, Peoples Republic of (China)
- Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States)
- Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831 (United States)
- Department of Physics, Mississippi State University, Mississippi 39762 (United States)
- Physics Department, Fisk University, Nashville, Tennessee 37208 (United States)
- Idaho National Engineering Laboratory, Idaho Falls, Idaho 83415 (United States)
- Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
- Universidade Federal do Rio de Janeiro, CP 68528, Rio de Janeiro (Brazil)
- Soreq Nuclear Research Center, Yavne (Israel)
- Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
- University of California, Berkeley, California 94720 (United States)
- Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russia)
Several new high-spin states are observed in the prompt {gamma}-rays emitted from the neutron-rich, odd-Z {sup 145,147}La fragments produced in the spontaneous fission of {sup 252}Cf. Alternating parity bands are extended up to spins 41/2 and 43/2 in {sup 145,147}La, respectively. A new band completes the evidence for two sets of parity doublets expected for octupole correlations. Eight B(E1)/B(E2) ratios (four new) between two bands in {sup 145}La are all essentially constant and somewhat larger than similar ratios in {sup 143,144}Ba, where stable octupole deformation and/or correlations are reported. The new ratios out of the 31/2{sup {minus}} levels in both nuclei show a sharp spike compared to other states, presumably from a strong reduction in E2 strengths in this backbending region. In {sup 145}La, collective bands show competition and coexistence between symmetric and asymmetric shapes. Band crossings occur in both nuclei around {h_bar}{omega}{approx}0.26{endash}0.30 MeV. Their backbends are associated with the alignment of two i{sub 13/2} neutrons according to cranked shell model calculations. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 322000
- Journal Information:
- Physical Review, C, Vol. 59, Issue 3; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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