Generalization of α-Decay Cluster-Model to Nuclei Near Spherical and Deformed Shell Closures

摘要

The duster model of α-decay is extended to the regions around doubly magic spherical nucleus ~(208)Pb and around deformed shell closure ~(270)Hs, respectively. The effects of spherical shell closures (N = 126 and Z = 82) on α-decay are investigated by introducing an N-dependent α-preformation factor and a Z-dependent one inspired by a microscopic model. Good agreement between the theoretical α-decay half-lives and the measured ones is obtained for the spherical nuclei near the doubly magic nucleus ~(208)Pb, where the nuclear shell effect is included in the expression of α-preformation factor. The cluster model is also generalized for the decay of deformed nuclei. The branching ratios of α-decays from the ground state of a parent nucleus to the ground state (0~+) of its deformed daughter nucleus and to the first excited state (2~+) are calculated in the framework of the cluster model. The results indicate that a measurement of α spectroscopy is a feasible method to extract the information of nuclear deformation of superheavy nuclei around the deformed nucleus ~(270)Hs.