A systematic investigation of α-decay and ß±-decay half-lives of Francium isotopes in the mass range 189 ≤ A ≤ 241 has been carried out. The α-decay half-lives were evaluated within the framework of the unified ternary fission model, while ß± -decay half-lives were calculated using established semi-empirical relations. The calculated results were compared with available experimental data and show good agreement, confirming the reliability of the adopted theoretical approaches. A clear transition in dominant decay modes is observed across the isotopic chain: neutron-deficient isotopes (A = 189-212) predominantly undergo α-decay (with an exception at 212Fr favoring ß+ decay), whereas neutron-rich isotopes (A ≥ 222) are mainly governed by ß− decay. Furthermore, detailed and consistent decay chains were predicted for previously less-explored isotopes, particularly 189-196Fr and 234-241 Fr, revealing systematic sequences of α- and β-transitions leading to stable daughter nuclei. These results provide deeper insight into the decay systematics and structural evolution of Francium isotopes.
Nagaraj et al. (Wed,) studied this question.