Effect of shell corrections on the α -decay properties of Fl280–305 isotopes

Abstract

The $\ensuremath{\alpha}$-decay half-lives of $^{285\text{--}289}\mathrm{Fl}$ isotopes and their decay chains are investigated by employing the generalized liquid-drop model (GLDM), the unified fission model, the Royer's analytical formula, and the universal decay law. For the GLDM, we take into account the shell correction. The agreement between the experimental data and the calculations indicates that all the methods we used are successful to reproduce $\ensuremath{\alpha}$-decay half-lives of $^{285\text{--}289}\mathrm{Fl}$. For the unknown nuclei, the $\ensuremath{\alpha}$-decay half-lives have been predicted by inputting $\ensuremath{\alpha}$-decay energies (${Q}_{\ensuremath{\alpha}}$) extracted from the finite-range droplet model and the updated Weizs\acker-Skyrme-4 (WS4) model. It is found that the shell correction would enlarge the calculated $\ensuremath{\alpha}$-decay half-lives in the region from $^{292}\mathrm{Fl}$ to $^{298}\mathrm{Fl}$, where the shell effects are evident. We confirm that $N=184$ is the neutron magic number and $N=178$ is the submagic number by analyzing the $\ensuremath{\alpha}$-decay half-lives and the shell correction energies. The competition between $\ensuremath{\alpha}$-decay and spontaneous fission is discussed in detail and the decay modes of $^{280\text{--}283}\mathrm{Fl}$ and $^{290\text{--}305}\mathrm{Fl}$ have been predicted. Our calculations are in good agreement with the experiments for the decay properties of $^{284\text{--}289}\mathrm{Fl}$. We also predict $^{284,286}\mathrm{Fl}$ with both $\ensuremath{\alpha}$-decay and spontaneous fission. The $^{280\text{--}283,290\text{--}295,297}\mathrm{Fl}$ isotopes are $\ensuremath{\alpha}$ decay, $^{300\text{--}305}\mathrm{Fl}$ undergo spontaneous fission, and $^{296,298,299}\mathrm{Fl}$ would have both $\ensuremath{\alpha}$-decay and spontaneous fission. We also predict the decay chains of $^{280\text{--}283,290,291}\mathrm{Fl}$.