الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The α-decay half-lives (T1/2) for 16 isotopic chains of even-even and even-odd nuclei, from 52Te to 82Pb were investigated by employing the density dependent cluster model. The α-nucleus potential was calculated by the double-folding model (DFM) using the M3Y-Reid NN interaction with the zero-range exchange part assuming spherical and deformed density distributions of the daughter nuclei. In the framework of the WKB approximation, the half-lives of the α-emitters were calculated and compared using six analytic formulas: the universal curve (UNIV), the universal decay law (UDL), the scaling law of Ho-roi, the BKAG, the NRDX and the TM formulas. We found a clear similarity in the behavior of log10 T1/2 versus the neutron daughter number (Nd) when the cal-culations performed using both DFM and these mentioned analytical formulas for each isotopic chain. In addition, the theoretical results of log10 T1/2 obtained with the UDL and UNIV formulas slightly better agree with the DFM calcula-tions than those calculated from the other analytical methods. The results point-ed out some magic or semimagic neutron numbers of the daughter nuclei corre-sponding to dips in the behavior of log10 T1/2 with variation in Nd. The interplay of these magic (semimagic) numbers is inspected as the total number of neutrons filling the upper neutron level in the parent nucleus. Starting from the number of neutrons needed for level closure and the available values of the confirmed spin of parent and daughter nuclei, we predicted the level schemes around the known magicities N = 50, 82, and 126. We found changes in the neutron levels for iso-topes of the same element which become too large for heavy nuclei. An example for these changes is the repetition of the spin value 1/2- for the three isotopes195-199Hg, with their three odd mass numbers, and their daughters, we need five dif-ferent neutron level arrangements with 3p1/2 level at the top