Features of Two-Quasiparticle Rotational Bands in Deformed Odd-Odd Nuclei, $156 \le A \le 168$

Abstract

In present work, we evaluated the experimental data pertains to two quasiparticle rotational structures in deformed odd-odd nuclei in rare earth mass region. The compilation includes total 234 rotational bands among which 173 are rotational bands and 61 bandhead states. Gallagher Moszkowski doublets are identified for 63 two quasiparticle configurations which provide a good testing ground for np residual interaction systematics. The highest excitation energies reach approximately 18 MeV in 164Lu and 168Lu nuclide. The triplet configuration becomes ground state in case of 22 nuclides namely 156-170Ho, 156-176Tm and 162-168Lu. Signature splitting is reported for 76 bands and signature inversion is identified in 29 bands which indicate the presence of Coriolis couplings and evolving configuration mixing with spin. The average signature splitting amplitudes lies between 12 to 300 keV. Band crossings have been observed in case of 10 bands, often accompanying changes in the kinematic and dynamic moments of inertia as paired high-j quasiparticles align with the rotational axis. Halflife information is available for 58 bandhead. The branching ratios and effective gfactors remain scares. In total, 137 bands display regular level sequences of energy levels whereas 8 exhibit irregular patterns. The present evaluation of two quasiparticle rotational bands reveals substantial gaps in the experimental data and highlight the need of fresh measurements to support rigorous calculations and reliable systematics.