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International audience; A detailed $\alpha$-decay spectroscopy study of $^{180}\mathrm{Tl}$ has been performed at ISOLDE (CERN). $Z$-selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of $^{180}\mathrm{Tl}$. Fine-structure $\alpha$ decays to excited levels in the daughter $^{176}\mathrm{Au}$ were identified and an $\alpha$-decay scheme of $^{180}\mathrm{Tl}$ was constructed based on an analysis of $\alpha$-$\gamma$ and $\alpha$-$\gamma$-$\gamma$ coincidences. Multipolarities of several $\gamma$-ray transitions deexciting levels in $^{176}\mathrm{Au}$ were determined. Based on the analysis of reduced $\alpha$-decay widths, it was found that all $\alpha$ decays are hindered, which signifies a change of configuration between the parent and all daughter states.

A detailed spectroscopic study of the neutron-deficient isotope 181Tl and the daughter of its alpha decay, 177Au, has been performed in the complete fusion reaction 40Ca+144Sm-->184Pb* at the velocity filter SHIP (GSI). The mass excess, excitation energy, and decay scheme of the isomeric 1.40(3) ms, 9/2- intruder state in 181Tl have been established for the first time. These results solve a long-standing puzzle of the unrealistically large reduced alpha-decay width of this isomer. Based on this, the previously unknown masses of the long-lived isomeric states in 177Au and 173Ir have been derived. In turn, it now allows the excitation energies of previously identified bands in 177Au and 173Ir to be deduced and compared with theoretical predictions. First measurements of alpha-decay branching ratios for 181Tlm and 177Aum,g are also reported