Particle-rotor model for doubly odd transitional nuclei of the Tl-region

Abstract

A model has been investigated describing a situation in which two noninteracting high- j Nilsson-BCS quasiparticles move in the deformed field of an axially and reflection symmetric rotor. According to the positions of the j-shells with respect to the proton and neutron Fermi surfaces structures of different character emerge referred to as semi- and doubly-decoupled. In particular, strongly Coriolis-distorted bands recently reported in doubly odd Tl nuclei are discussed. Alsotilde π h_{9/2} bands in neighbouring odd mass Tl isotopes are analysed on the same footing. It is shown that the pronounced odd even staggering of the transition energies can be understood as a specific quantal feature associated with the Coriolis interaction.