Comprehensive study of alpha-nuclei

Comprehensive study of alpha-nuclei has been made to investigate the molecule-like structure in nuclear many-body system. At first, the study on the structure of 12C is described. The discussions are based on the microscopic 3He particle models (generator coordinate method, orthogonality condition model, and resonating group method). The coexistence of shell-like and molecule-like structures and the structural change between them are discussed. The molecule-like structure of 16O as (12C) + alpha and the shell model character are studied. The structure of 20Ne was considered as 16O plus one alpha or 12C plus two alphas. The cluster model study of 24Mg structure was mainly based on the 16O plus two-alpha model. The calculations were carried out by using the orthogonality condition model (OCM) for the inter-cluster Hamiltonian. Almost all observed levels below 10 MeV were well reproduced. Discussions are given to the relation of the cluster model wave function for compact cluster configuration with the shell model wave function, the Pauli repulsion of composite particle interaction, the orthogonality between different kings of structures and its reflection to composite particle interaction, and the distance between different kings of structures. Discussions on the cluster model of nucleosynthetic process in stellar evolution, breaking of spatial symmetry, and the cluster phenomena in the nuclei with large mass number are also presented. (Kato, T.)