Prolate and oblate band structures in odd-odd Au186,188

High-spin states have been populated in odd-odd Au186,188 via the heavy-ion Yb171,173(19F,4n) reactions at 93–94 MeV. Rotational bands built on 11- oblate νi13/2-1⊗πh11/2-1 structures have been observed in both nuclei, similar to those reported in Au190-194. Two new strongly coupled bands in Au186 are interpreted as prolate πh9/2⊗νi132 and πi13/2⊗νi13/2 configurations. Based on blocking arguments a band crossing in the latter structure is attributed to the alignment of h9/2 protons. Measured B(M1;I→I-1)/B(E2;I→I-2) ratios are compared to predictions of the Dönau and Frauendorf geometrical formalism extended to odd-odd cases.