Theoretical calculations of the nuclear deformation effects on α-decay half-lives for heavy and super-heavy nuclei

alpha-decay half-lives of heavy and super-heavy even-even nuclei, in the range of Z = 80-118, were studied using an improved generalized liquid drop model, in which the deformation effects of both the parent and daughter nuclei are considered. The calculated values reflect a better accuracy of the agreement when compared with the experimental data of known nuclei from Hg to Og. The corresponding standard deviation reduced to 0.3670, which proves that the employed method is reliable to reproduce the alpha-decay half-lives. Semi-empirical formulas like the Royer formula and the universal decay law were also used for systematic calculations of alpha-decay half-lives. Based on a detailed analysis of the deformation effects in heavy and super-heavy nuclear regions, it was found that the nuclear deformation has a stronger influence on the super-heavy region. The competition between alpha-decay and spontaneous fission (SF) was also studied and it was observed that for some isotopes from Pu to Fl, the competition between two decay modes is intense, which reflects that these nuclei may follow both decay modes. A neutron magic number, N = 184, and sub-magic numbers, N = 152 and 162 were observed after the analysis of the alpha-decay half-lives and the SF half-lives of unknown even-even nuclei.