Systematic study on the competition between α-decay and spontaneous fission of superheavy nuclei

The competition between alpha-decay and spontaneous fission (SF) of Z = 112 isotopes are studied. The alpha-decay half-lives are estimated by the generalized liquid-drop model (GLDM) and several sets of analytic formulas. These formulas include the Royer formula, ViolaSeaborg semiempirical (VSS) formula and universal decay law (UDL). For the SF, its half-lives are calculated by using the Xu, Ren, Karpov and Santhosh formulas. It is shown that the predicted ?-decay half-lives by different approaches are more or less identical. However, the SF half-lives are highly sensitive to models. To test the accuracies of different SF formulas, the half-lives of 56 eveneven heavy nuclei are calculated by these formulas. By comparing with the experimental data, it is found that the Xu formula is the most accurate one to reproduce the experimental SF half-lives. This allows us to make a systematic prediction on the competition between ?-decay and SF of eveneven superheavy nuclei (SHN) with Z = 104-120 by using the Xu formula and the above mentioned models on alpha-decay. The calculations suggest that (258,260)104, (268-276)110, (270-280)112, (272-286)114, (274-294)116, (284-302)118 and (292-308)120 have smaller alpha-decay half-lives than those of SF. Thus these nuclei can be synthesized and identified via alpha-decay in the laboratory. In addition, it is observed that N =162, , 178, 184 and 196 may be the submagic or magic numbers. Finally, an extensive study on the possible alpha-decay chains for Z =120 isotopes is performed. It is predicted that six sequential alpha-decay chains can be observed from (292-296)120, four alpha-decay chains from (298)120, three alpha-decay chains from (300,302)120, two alpha-decay chains from (304,306)120, and only one alpha-decay chain from (308)120. These nuclei are the most likely candidates to be synthesized experimentally via alpha-decay in the near future. (C) 2017 Elsevier B.V. All rights reserved.