Cluster radioactivity of ${}_{118}{}^{294}\mathrm{Og}_{176}$

According to theory, cluster radioactivity becomes an important decay mode in superheavy nuclei. In this work, we predict that the strongly asymmetric fission, or cluster emission, is in fact the dominant fission channel for ${}_{118}{}^{294}\mathrm{Og}_{176}$, which is currently the heaviest synthetic isotope known. Our theoretical approach incorporates important features of fission dynamics, including quantum tunneling and stochastic dynamics up to scission. We show that despite appreciable differences in static fission properties such as fission barriers and spontaneous fission lifetimes, the prediction of cluster radioactivity in ${}_{118}{}^{294}\mathrm{Og}_{176}$ is robust with respect to the details of calculations, including the choice of energy density functional, collective inertia, and strength of the dissipation term.

Figure 1

Comparison of the PESs for ${}_{118}{}^{294}\mathrm{Og}_{176}$ in the $(Q_{20},Q_{30})$ collective plane obtained in the three EDFs. The ground-state energy $E_{\mathrm{g}.\mathrm{s}.}$ is normalized to zero. The dotted line in each figure corresponds to $E_0-E_{\mathrm{g}.\mathrm{s}.}=1$ MeV, which was used to determine the inner and outer turning points. The local energy minima at large deformations are marked by stars.

Figure 2

Fission fragment distributions for ${}_{118}{}^{294}\mathrm{Og}_{176}$ obtained in the three EDFs using the nonperturbative cranking ATDHFB inertia and the baseline dissipation tensor ${\mathbf{\eta }}_0$. Known isotopes are marked in grey [55]. Magic numbers 50, 82, and 126 are indicated by dotted lines.

Figure 3

Upper: Predicted heavy fragment mass and charge yields of ${}_{118}{}^{294}\mathrm{Og}_{176}$ using different functionals (top, linear scale). Lower: collective inertias and dissipation tensor strengths (in logarithmic scale). The baseline calculation was performed using the $\mathrm{UNEDF}{1}_{\mathrm{HFB}}$ functional in a 4D space with nonperturbative cranking ATDHFB inertia and dissipation tensor strength ${\mathbf{\eta }}_0$.

Figure 4

Nucleon localization function for a highly deformed configuration of ${}_{118}{}^{294}\mathrm{Og}_{176}, (Q_{20},Q_{30})=(264\mathrm{b},60{\mathrm{b}}^{3/2})$ for neutrons and protons. For comparison, localizations are shown for the prefragments ${}_{\phantom{2}82}{}^{208}\mathrm{Pb}_{126}$ and ${}_{36}{}^{86}\mathrm{Kr}_{50}$ on the left side of each subplot.