Spontaneous fission half-lives of the heaviest nuclei: Semi-empirical predictions

Abstract

The spontaneous fission half-lives in superheavy nuclei are predicted by theoretical approaches from the order of few years up to the age of the earth. In this work, all known experimental spontaneous fission half-lives of nuclei with Z>95 have been used for the extraction of the effective widths of the parabolic fission barriers with heights from two different theoretical models: FRLDM and ETFSI. The results are discussed with consideration on the shape of the fission barriers for the particular models. By extrapolating the extracted widths of the parabolic barrier, and the calculated fission-barrier heights from the two models, the spontaneous fission half-lives for nuclei with Z=98−120 were calculated within the presently suggested semi-empirical approach. Two theoretical models results in completely different scenarios for the shape of fission barrier in superheavy nuclei. Interestingly, the results with FRLDM predict that spontaneous fission in superheavy nuclei and in particular Z=120, may compete with α decay, and thus the spontaneous fission branches of these nuclei are significant enough such that they should be considered during experimental studies.