Alpha-decay Half-lives and Fission Barriers for Superheavy Nuclei Predicted by a Nuclear Mass Formula

抄録

We estimate α-decay half-lives from Q_{α} values with phenomenological formulas. The parameter values of the formulas are adjusted by using experimental half-lives and Q values of the Evaluated Nuclear Structure Data File (ENSDF) for a wide nuclidic region. The half-lives T_{α} for unknown nuclei are estimated by this phenomenological formula with the use of Q_{α} values taken from KUTY mass formula. In addition to the half-lives, we estimate spontaneous fission barriers calculated by the method to obtain the shell energies of KUTY formula. In the superheavy region, the barrier heights of the nuclei near the nucleus ³⁰⁴ 122 are about 8 MeV and their widths are fairly wide. Therefore these spontaneous-fission half-lives are expected to be very long. On the other hand, there are some neutron-deficient nuclei whose spontaneous-fission half-lives expected to be rather short because their fission barrier heights are small and the widths of them are narrow.