Levels in Even-Even ${\mathrm{Hg}}^{192}$, ${\mathrm{Hg}}^{194}$, ${\mathrm{Hg}}^{196}$, and ${\mathrm{Hg}}^{198}$

The decay of the $2^{-}$ and $7^{+}$ isomeric states of ${\mathrm{Tl}}^{192}$, ${\mathrm{Tl}}^{194}$, ${\mathrm{Tl}}^{196}$, and ${\mathrm{Tl}}^{198}$ has been studied, using isotopically separated sources produced by high-energy proton spallation of lead and uranium targets. $\gamma$-ray and conversion-electron spectra have been recorded, and extensive coincidence measurements have helped to establish the energy levels that are populated in the corresponding mercury daughter nuclides. Level schemes for ${\mathrm{Hg}}^{192}$, ${\mathrm{Hg}}^{194}$, ${\mathrm{Hg}}^{196}$, and ${\mathrm{Hg}}^{198}$ deduced from the data are presented and discussed.