Oblate collectivity inPb197

Abstract

Evidence for collective behavior in the high-spin region of lead nuclei is provided by the observation of two collective structures in ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pb}$. One of these bands is interpreted as an oblate collective structure built on oblate proton and possibly neutron states. A second more irregular band is suggested to be most likely a triaxial rotational band. Neutron and proton configurations for these bands are suggested from the results of quasiparticle Routhians and total Routhians surface calculations. A partial level scheme up to I≊69/2 and ${\mathit{E}}_{\mathit{x}}$≊8 MeV is presented.