New oblate band inHg196with quenchedM1 strength

High-spin states in the nucleus ${}_{}{}^{196}{}_{}{}^{}\mathrm{Hg}$ were populated in the reaction ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$ ${(}^9$Be,5n) at a beam energy of 65 MeV. A regular rotational-like ΔI=1 band has been observed up to an excitation energy of ${\mathit{E}}^{\mathrm{*}}$≊8.7 MeV and spin I≊30ħ. This is the second observation of a band of this character in a mercury isotope. The experimental results are compared with mean field calculations and semiclassical estimates based on the Dönau-Frauendorf formalism. The mercury bands show significantly lower B(M1)/B(E2) branching ratios as compared with similar bands in light lead nuclei. This difference may be more readily explained by a difference in single-particle structure rather than by large differences in deformation between the lead and mercury configurations.