A six-quasiparticle isomer with $T{}_{1/2}$ = 57(2) ns has been established in the doubly-odd isotope ${}^{200}\mathrm{Tl}$ and its level scheme is significantly extended. Half-lives of previously reported isomers in ${}^{200}\mathrm{Tl}$ and ${}^{201,202}\mathrm{Pb}$ have been determined and revised values are reported in a few cases, with $T{}_{1/2}$ = 397(17) ns and 7.0(5) ns for the ${\mathit{I}}^{\pi }=5^{+}$ and $7^{-}$ states in ${}^{200}\mathrm{Tl}$, 52(2) ns for the $41/2^{+}$ level in ${}^{201}\mathrm{Pb}$, and 93(4) ns for the ${16}^{+}$ state in ${}^{202}\mathrm{Pb}$. Configurations for the isomers have been assigned and these predominantly involve intrinsic excitations of neutrons from the $i_{13/2}$ subshell. The inferred transition rates for the decay of these isomers compare well with single-particle estimates attesting to their intrinsic character.

• Received 20 June 2019
• Revised 10 July 2019

DOI:https://doi.org/10.1103/PhysRevC.100.024320