Particle-core coupling calculations have been made for the $h_{9/2}$ bands in the odd-Tl isotopes (A=191–197) and the $h_{11/2}$ bands in the odd-Au isotopes (A=189–195). The even-mass Hg core descriptions were taken from previous proton-neutron interacting boson model calculations, and thus a comparison between the experimental and calculated level schemes for the Tl and Au isotopes can be interpreted as a test of the core description. A predicted transition from positive Q${(2\mathrm{}}^{+}$) near A=195 to negative Q${(2\mathrm{}}^{+}$) near A=191 is not borne out by the odd-A data. These results, combined with new proton-neutron interacting boson model calculations, indicate that the Hg isotopes are more U(5) than O(6) in character.

• Received 22 September 1986

DOI:https://doi.org/10.1103/PhysRevC.35.844