Mahmoud Yahia Ismail

We systematically investigated the behavior of the α-decay half-lives (Tα) for 20 isotopic chains of even–even nuclei, from 78Pt to 116Lv. Tα is calculated within the preformed cluster model. The α-core potential is determined by the double-folding model based on the M3Y-Reid nucleon–nucleon interaction. The Coulomb potential is also microscopically calculated by the folding procedure. To confirm our results, we used four different parameterizations of the involved proton and neutron densities, which are consistent with extensive microscopic calculations and electron scattering data. The results correlate the logTα behavior for the isotopes of an element with their proton energy levels. We found a clear similarity in the behavior of logTα with the number of neutrons of the daughter nuclei (Nd) for specific isotopic chains. The proton pairs forming the α-particles that emitted from the isotopes of the similar chains belong to the same proton energy level. We pointed out some neutron magic and semi-magic numbers corresponding to characteristic minima in the logTα variation with Nd. We interpreted these magic (semi-magic) numbers as the total number of neutrons filling the upper neutron level in the parent nucleus.

The authors investigate the proximity scaling for the nuclear part of the nucleus-nucleus potential derived from the collision of two infinite nuclear matters flowing through each other. It is found that the proximity theorem is satisfied to a good extent at each value of the projectile energy per nucleon. They simplify the interaction potential between different pairs of nuclei by the product of a geometrical factor, dependent on the radii of the interacting nuclei, and a gaussian distribution whose parameters depend on the projectile energy per nucleon.