Shape coexistence in 119,121I: Insights from the triaxial projected shell model

A theoretical investigation on shape coexistence in the isotopes [Formula: see text]I and [Formula: see text]I has been carried out using both the Projected Shell Model (PSM) and Triaxial Projected Shell Model (TPSM). We analyze the energy spectra, band structures, potential energy surfaces and signature splitting for these nuclei. Our study reveals that the yrast band for [Formula: see text]I is better described by TPSM with [Formula: see text] and the yrast band of [Formula: see text]I is described by PSM (Prolate) at low spins and by TPSM with [Formula: see text] at higher spins. In contrast, the yrast band exhibits predominantly an oblate character for both [Formula: see text]I and [Formula: see text]I isotopes. The intrinsic structures of these isotopes have been discussed by interpreting their band diagrams. Also, signature splitting in these isotopes obtained via PSM and TPSM has been compared with experimental observations to mark some significant conclusions.