Theoretical investigation on the concept of double-α (2α) decay is studied in the framework of the modified generalized liquid drop model with different preformation parameters. Comparison of 2α and ${}^8\mathrm{Be}$ emission from various nuclei reveals that 2α emission is more probable than ${}^8\mathrm{Be}$ emission, and ${}^8\mathrm{Be}$ emission does not occur due to its highly unstable nature. Probable 2α emitters are investigated for nuclei in the natural isotopic compositions of elements with atomic numbers varying from 60 to 92 and our predictions on half-lives are in agreement with the values reported by Tretyak [Nucl. Phys. At. Energy. 22, 121 (2021)] using the semiempirical formula for cluster decays. The computed 2α half-life of ${}^{209}\mathrm{Bi}$ using the SemFIS formula is found to be $1.926\times {10}^{15}\mathrm{yr}$ and is compared with the first reported experimental limit $(T_{1/2}>2.9\times {10}^{20}\mathrm{yr})$ estimated from the experimental data of de Marcillac et al. [Nature (London) 422, 876 (2003)]; and this observation demonstrates the possibility of the detection of 2α decay from the ${}^{209}\mathrm{Bi}$ isotope. We have also predicted 2α half-lives for various isotopes ${}^{191\text{–}226}\mathrm{At}$, ${}^{193\text{–}228}\mathrm{Rn}$, ${}^{197\text{–}232}\mathrm{Fr}$, ${}^{201\text{–}235}\mathrm{Ra}$, ${}^{205\text{–}237}\mathrm{Ac}$, Th, ${}^{212\text{–}241}\mathrm{Pa}$, ${}^{215\text{–}243}\mathrm{U}$, and ${}^{219\text{–}245}\mathrm{Np}$, and most of the decay half-lives are below the measurable upper limit thereby promising chances to enhance experimental investigations on 2α decay in the future.

• Received 31 July 2021
• Revised 26 October 2021
• Accepted 24 November 2021
• Corrected 25 February 2022

DOI:https://doi.org/10.1103/PhysRevC.104.064604