The Systematic Structure-Change into the Molecule-like Structures in the Self-Conjugate $4n$ Nuclei

The rotational bands with the diatomic-molecule-like structure in the self-conjugate 4n light nuclei, such as, α-α, α-12C and α-16O, appear systematically at near the threshold energy for the decay into the relevant subunit nuclei. The relations between the structure change into the molecule-like structure and the threshold energy for the decay into the subunit nuclei are discussed. According to this discussions, the diagram for the systematic structure change into the molecule-like structures through the alpha particle release is presented as the function of the mass number and the energy. Upon this diagram the rotational bands with K = 0± in light 4n nuclei can be summarized. The order of the degree of the polarization toward the separation of the subunit nuclei for the diatomic molecule-like structure case is discussed qualitatively.