A conceptually different interpretation of the excitation energies and signature inversion in negative parity bands of odd-Z and odd-N nuclei has been given within the framework of triaxial rotor plus one quasiparticle model. Furthermore, in the present work, evidence has been obtained for a triaxial shape transition in these nuclei related to a sudden decrease in the signature splitting.

• Received 2 August 1993

DOI:https://doi.org/10.1103/PhysRevC.49.142