Band structures and intruder πi13/2 state in 197Tl

The excited states in the odd-A Tl-197 nucleus have been studied by populating them using the Au-197(alpha, 4n)Tl-197 reaction at a beam energy of 48 MeV. The gamma-gamma coincidence data were taken using a combination of clover, low-energy photon spectrometer (LEPS), and single-crystal high-purity germanium (HPGe) detectors. Precise spin and parity assignments of the excited states have been done through polarization and directional correlation from oriented states (DCO) measurements. A new band structure has been identified and evidence for a possible intruder pi i(13/2) state has been found for the first time. Possible configurations of the observed bands have been discussed. The total Routhian surface calculations have been performed to study the shape of Tl-197 for different configurations.