Systematic Study on Alpha Decay Half-Lives of Superheavy Nuclei

The α-decay half-lives of a set of superheavy nuclear isotopechain from Z=105 to 120 have been analyzed systematically within theWKB method, and some nuclear structure features are found. The decaybarriers have been determined in the quasi-molecular shape path within the Generalized Liquid Drop Model (GLDM) including the proximity effects between nucleons in a neck and the mass and charge asymmetry. The results are in reasonable agreement with thepublished experimental data for the alpha decay half-lives of isotopes of charge 112, 114, and 116, of the element ²⁹⁴118 and ofsome decay products. A comparison of present calculations with theresults by the DDM3Y effective interaction and by theViola-Seaborg-Sobiczewski (VSS) formulae is also made. Theexperimental α decay half lives all stand in between the GLDMcalculations and VSS formula results. This demonstrates the possibility of these models to provide reasonable estimates for the half-lives of nuclear decays by α emissions for the domain of SHN. The half-lives of these new nuclei are thus well tested fromthe reasonable consistence of the macroscopic, the microscopic, theempirical formulae and the experimental data. This also shows that the present data of SHN themselves are consistent. It could suggest that the present experimental claims on the existence of new elements Z=110～118 are reliable. It is expected that greaterdeviations of a few SHN between the data and the model may beeliminated by further improvements on the precision of the measurements.