Deformed band structures at high spin in 200Tl

Abstract

High-spin band structures of 200Tl have been studied by γ -ray spectroscopic methods using the 198Pt(7 Li ,5n) 200Tl reaction at 45 MeV of beam energy. The level scheme of 200Tl has been extended significantly and several new band structures have been established with the observation of 60 new transitions. The πh9/2 ⊗ νi13/2 oblate band has been extended beyond the particle alignment frequencies. The band structures and the other excited states have been compared with the neighboring odd-odd Tl isotopes. Total Routhian surface calculations have been performed to study the deformation and shape changes as a function of spin in this nucleus. These calculations could reproduce the particle alignment frequency and suggest that the neutron pair alignment in νi13/2 orbital induces γ softness in 200Tl.