Theoretical predictions for $\alpha$-decay properties of ^283-339Og using a shell-effect induced generalized liquid-drop model

Abstract.

The $\alpha$-decay half-lives of synthesized superheavy nuclei (SHN) from seaborgium to oganesson are calculated by employing the generalized liquid-drop model (GLDM), the Royer formula and the universal decay law (UDL) with experimental $\alpha$-decay energies $Q_{\alpha}$. For the GLDM, we consider the shell correction. The agreement between the experimental data and the calculations indicates that all the methods we used are successful to reproduce $\alpha$-decay half-lives of known SHN. The decay-modes of known nuclei on the ²⁹⁴Og decay-chain are also consistent with the experiments. For the unknown nuclei, the $\alpha$-decay half-lives have been predicted by inputting $Q_{\alpha}$ values extracted from the newest Weizsäcker-Skyrme-4 (WS4) model. In the GLDM with shell correction, we adopt the constant $\alpha$-preformation factor $P_{\alpha}$ as well as $P_{\alpha}$ extracted by Cluster Formation Model (CFM). To calculate CFM $P_{\alpha}$ values, we use FRDM binding energies and WS4 mass excess values. The relationship of $P_{\alpha}$ and $Q_{\alpha}$ shows that ^{294, 296, 314, 316, 320}Og isotopes are relatively stable. The competition between $\alpha$-decay and spontaneous fission is discussed in detail for ^283-339Og isotopes. The decay-chains of ^290-300Og have also been presented. Since the $\alpha$-decay half-lives of ^283-303Og isotopes are obviously lower than their spontaneous fission half-lives by more than 6 orders, these isotopes would mainly have $\alpha$-decay. The ^306-334Og isotopes may undergo spontaneous fission. The nuclei ^{304, 305}Og would have both $\alpha$-decay and spontaneous fission. By the shell-effect included GLDM with CFM $P_{\alpha}$, we predict ²⁹⁵Og undergoes $\alpha$-decay and $T_{\alpha}^{1/2} = 0.37$ ms. The ²⁹⁶Og is also $\alpha$-decay and has $T_{\alpha}^{1/2} = 0.40$ ms.