Low-lying proton-based intruder states have been observed in the odd-mass isotopes ${}^{189,191,193}\mathrm{Pb}$ in experiments at the RITU gas-filled recoil separator. The identification has been performed by observing the fine structure in the $\alpha$ decay of the parent ${}^{193,195,197}\mathrm{Po}$ nuclei in prompt coincidence with conversion electrons and $\gamma$ rays in the daughter lead isotopes. Along with the literature data these results establish a systematics of intruder states in the odd-mass lead isotopes from ${}^{197}\mathrm{Pb}$ down to ${}^{185}\mathrm{Pb}.$ Interpretation of these states involves the coupling of the ${1i}_{13/2}$ or ${3p}_{3/2}$ odd neutron to the $0^{+}$ state in the oblate minimum in the even-mass lead core. Conversion coefficients have been determined for some of the transitions, revealing mixing between the coexisting states. The experimental results are compared to potential energy surface calculations.

• Received 4 March 2002

DOI:https://doi.org/10.1103/PhysRevC.65.064301