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 Weizsacker-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, 320Og 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, 305Og 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.