E3 strength of the 11{sup -} to 8{sup +} isomeric decays in {sup 194}Pb and {sup 196}Pb and oblate deformation

• Published in: Physical review. C, Nuclear physics Nuclear physics, 2005-12, Vol.72 (6)
• Main Authors: Dracoulis, G.D., Lane, G.J., Peaty, T.M., Baxter, A.M., Davidson, P.M., Kibedi, T., Byrne, A.P., Wilson, A.N., Department of Nuclear Physics, RSPhysSE, Australian National University, Canberra ACT 0200, Xu, F.R.
• Format: Article
• Language: English
• Subjects: CONFIGURATION MIXING; E3-TRANSITIONS; ISOMERIC NUCLEI; KEV RANGE; LEAD 194; LEAD 196; LIFETIME; NUCLEAR DECAY; NUCLEAR DEFORMATION; NUCLEAR PHYSICS AND RADIATION PHYSICS; POTENTIAL ENERGY; PROTONS; SURFACES
• ISSN: 0556-2813; 1089-490X
• DOI: 10.1103/PhysRevC.72.064319

The E3 decays of the 11{sup -} isomers in the isotopes {sup 194}Pb and {sup 196}Pb have been studied experimentally and evaluated in terms of configuration mixing due to the development of oblate deformation. New results include a remeasurement of the lifetime of the 11{sup -} isomer in {sup 194}Pb and clarification of the intensities of its main decay branches including the known 496 keV E3 branch. Its intensity is an order of magnitude weaker than previously reported, leading to an E3 transition strength of 29(4) W.u. Limits are placed on possible E3 decays of the 11{sup -} isomer in {sup 196}Pb to a previously assigned 8{sup +} two-proton state. Neither the branch, nor the state is observed. An alternative 562 keV transition to a new state at 2630 keV is proposed, with an E3 strength of 26(2) W.u. The approximately constant E3 strength for the range of even-even isotopes {sup 190-196}Pb is consistent with an oblate deformation for the 11{sup -} state of similar magnitude. This is supported by K-constrained potential-energy-surface calculations for the 11{sup -} and 8{sup +} configurations.