High spin spectroscopy of 201Tl

The high spin structure of Tl-201 has been studied by gamma-ray spectroscopic method using the Pt-198(Li-7,4n)Tl-201 reaction at 45 MeV beam energy. The level scheme of Tl-201 has been considerably extended through the observation of 31 new transitions. Several new band structures have been established. The 9/2(-) oblate band has been significantly extended beyond the particle alignment frequencies. The band structures and the other excited states have been compared with the neighboring odd-A Tl isotopes and with the even-even core nucleus Hg-200. The total Routhian surface calculations have been performed to study the deformation and shape changes as a function of spin in this nucleus.