Shape coexistence studied in ${}^{\mathrm{182,184}}$Hg via the β decay of ${}^{\mathrm{182,184}}$Tl

The ${\beta }^{+}$/EC decay of ${}^{\mathrm{182,184}}$Tl to excited states in the daughter nuclei ${}^{\mathrm{182,184}}$Hg has been investigated at the CERN on-line isotope mass separator facility. In both Tl nuclei two β-decaying states were observed. In the case of (184)Tl, narrow-band laser spectroscopy could be used to disentangle the decay of both isomers. In (182)Hg a precise energy of 335 (1) keV for the ${0}_{2}^{+}$ state was measured together with its feeding from a tentatively proposed ${2}_{3}^{+}$ state at 973 keV. Large conversion coefficients for the ${2}_{2}^{+}\to {2}_{1}^{+}$ transition in ${}^{\mathrm{182,184}}$Hg were measured to be 7.2 (13) and 14.2 (36), respectively, evidencing a strong E0 component.