β-Decay Properties of Neutron-Rich Xe, I, and Te Isotopes in the Mass Region A = 120–146

In this paper, microscopic calculations of the β-decay properties of selected Xe, I, and Te isotopes in the mass region A = 120–146 were performed within the framework of the proton–neutron quasiparticle random-phase approximation (pn-QRPA). The investigated nuclei extend from the vicinity of the valley of stability toward the neutron-rich region. Allowed Gamow–Teller (GT) transitions were calculated within the Schematic Model (SM) by including both particle–particle (pp) and particle–hole (ph) residual interactions, whereas first-forbidden (FF) transitions were treated within the schematic model by considering the particle–hole (ph) channel. Woods–Saxon single-particle energies were adopted as the mean-field basis, and all nuclei were assumed to be spherical. The calculated total β-decay half-lives, logft values, and transition strengths were systematically compared with the available experimental data and previous theoretical calculations. Overall, satisfactory agreement was obtained for both allowed and first-forbidden transitions. The microscopic structure of the calculated GT and FF resonance states was further analysed using their dominant proton–neutron two-quasiparticle configurations and the corresponding pn-QRPA amplitudes, thereby providing additional insight into the origin of the transition strengths. The fulfillment of the Ikeda sum rule confirms the internal consistency of the calculations. This paper also provides theoretical predictions for several transition channels for which experimental information is currently unavailable, offering useful benchmark data for future experimental investigations and nuclear-structure and astrophysical applications.