In this article, the radioactivity and stability properties of samarium (Z = 62) isotopes are structurally analyzed within the framework of the Symmetric Skeleton Structure (SSS) approach. While in classical nuclear models isotope stability is mainly explained through energetic minima and shell closures, here the decisive role of the geometric and mechanical organization of the nucleus is emphasized. According to the SSS model, protons form a symmetric skeleton arranged in concentric layers within the nucleus, and the distribution of neutrons—particularly in the equatorial layer—determines mechanical equilibrium. In the samarium isotope chain, the neutron-deficient zone, the stability interval, and the neutron-excess zone are differentiated based on structural criteria; within the stability interval, lower sensitive, non-sensitive, and upper sensitive sub-zones are distinguished. The results show that radioactivity mechanisms in these zones arise from different structural causes, and an odd neutron number in the equatorial layer may be associated with the disruption of internal mechanical equilibrium.
Alikhan Mammadaliyev (Fri,) studied this question.