Two triaxial states of the proton-decaying nucleus ${}^{147}\mathrm{Tm}$ were studied via a comparison of experimental data to results obtained through nonadiabatic quasiparticle calculations. The experimental data were collected in a recoil-decay tagging study using the vacuum-mode recoil separator MARA coupled with the JUROGAM3 $\gamma$-ray spectrometer. The previously proposed level scheme above the triaxial $11/2^{-}$ $\left(\pi h_{11/2}\right)$ ground state was confirmed, and the level structure was expanded to cover the states above the weakly populated proton-emitting $5/2^{+}$ $\left(\pi d_{5/2}\right)$ isomeric state. It was found that the isomeric state is also triaxial, and possibly more deformed than the ground state.

• Received 21 March 2023
• Accepted 20 June 2023

DOI:https://doi.org/10.1103/PhysRevC.108.L011303