Close near-degeneracy in a pair of four-quasiparticle bands in 194Tl

A pair of rotational bands associated with the πh9/2⊗νi13/2−1 configuration at lower spins and with the πh9/2⊗νi13/2−3 configuration at higher spins is found in 194Tl. The two 4-quasiparticle bands show exceptionally close near-degeneracy in the excitation energies. Furthermore close similarity is also found in their alignments and B(M1)/B(E2) reduced transition probability ratios. Such close near-degeneracy probably indicates chiral geometry in the angular momentum space.