Insights into triaxial collectivity of odd-mass 111−119Sb isotopes

Abstract

High-spin structures of odd-mass ${}^{111-119}$Sb isotopes are investigated using the Triaxial Projected Shell Model (TPSM), with deformation parameters extracted from constrained Covariant Density Functional Theory (CDFT) calculations. The band diagrams exhibit characteristic crossings between one- and three-quasiparticle (1-qp and 3-qp) configurations in the mid-spin region, which are explained through the evolution of 3-qp wavefunction amplitudes. These structural changes are reflected in alignment diagrams, signature splitting and transition probabilities. The study demonstrates the necessity of including multi-quasiparticle configurations in the model basis to accurately reproduce experimentally observed electromagnetic transition rates particularly in ¹¹³Sb. Angular momentum projections, evaluated across three intrinsic sectors, provide direct evidence for triaxiality in this isotope. Overall, this work offers new insights into the influence of triaxial deformation and quasiparticle dynamics on the rotational behavior of Sb nuclei near the Z = 50 shell closure.