Valleys due to Pb and Sn on the potential energy surface of superheavy and lighter α-emitting nuclei

Abstract

The strong shell effects of the magic nuclei 208Pb, 132Sn and 102Sn are the origin of valleys on the potential energy surfaces (PES) of the superheavy nucleus 294118 and of the alpha emitters 212Po and 106Te. We use the most advanced asymmetric two-centre shell model allowing us to obtain shell and pairing corrections which are added to the Yukawa plus exponential model deformation energy. For the first time the alpha valley of a nucleus (106Te) calculated by using the macroscopic–microscopic method is clearly seen on a PES. The α-decay half-lives calculated within fission theories (analytical superasymmetric fission model, universal curve, semiempirical formula based on fission theory) are very close to the experimental ones. The increased deviations in the neighbourhood of magic numbers of nucleons, present in other frequently used relationships (e.g. Viola–Seaborg formula), are smoothed out by the semiempirical formula based on fission theory.