Search

High-spin spectroscopy on odd-odd ${}^{164}\mathrm{Tm}$ has produced new illustrations of departures from the predictions of principal-axis cranking. Among the nine strongly coupled rotational bands observed, four are assigned to the parallel and antiparallel couplings of two configurations $\ensuremath{\pi}{h}_{11/2}\ensuremath{\nu}{i}_{13/2}$ and $\ensuremath{\pi}{g}_{9/2}\ensuremath{\nu}{i}_{13/2}.$ This represents the first time that the high-spin properties of both couplings can be explored. We find that the measured $B(M1)/B(E2)$ values in the $K=1(\ensuremath{\uparrow}\ensuremath{\downarrow})$ coupling of $\ensuremath{\pi}{h}_{11/2}\ensuremath{\nu}{i}_{13/2}$ are 50% larger than those in the $K=6$ (\ensuremath{\uparrow}\ensuremath{\uparrow}) coupling, and represent the largest seen in this nucleus. Tilted-axis cranking calculations successfully explain the $M1/E2$ ratios in these two bands, while the particle-rotor calculations did not reproduce the full low-K enhancement. No inversion in the signatures of the $K=6\ensuremath{\pi}{h}_{11/2}\ensuremath{\nu}{i}_{13/2}$ band is observed, but there is a small inversion in the $K=1$ coupling up to $I=17\ensuremath{\Elzxh}$ and a large inversion in the $\ensuremath{\pi}{h}_{9/2}\ensuremath{\nu}{i}_{13/2}$ band up to $I=19\ensuremath{\Elzxh}.$ Remarkably, particle-rotor calculations with a $p\ensuremath{-}n$ interaction included are able to reproduce these inversions. A stronger $p\ensuremath{-}n$ interaction is needed to explain an inversion in the $\ensuremath{\pi}{d}_{3/2}\ensuremath{\nu}{i}_{13/2}$ band.