High-spin states in ¹⁹¹Au: Evidence for triaxial shape?

The level scheme of ¹⁹¹Au was considerably extended to high spin using γ spectroscopy with the Eurogam-II array and internal conversion measurements with the Orsay electron spectrometer. Several bands that appear as strongly coupled were associated with low-Ω configurations in ¹⁹¹Au. Using total routhian surface and cranked shell model calculations it was shown that these bands have a rotation-aligned nature and are most likely generated by the nonaxiallity of the nucleus induced by the odd proton. The predictions for the presence of such bands in ¹⁹¹Au and in the oblate nuclei in the Pt-Au-Hg region found excellent agreement with the experimental data, as well as the predictions for their alignments and band-crossing frequencies in ¹⁹¹Au.