Chapter II. Theory of Resonating Group Method and Generator Coordinate Method, and Orthogonality Condition Model

Abstract

Theory of the resonating group method (RGM) for describing microscopically interactions between nuclei (clusters) is reviewed briefly. Especially formulations on the description are presented. It is shown that the generator coordinate method (GCM) is a very useful and successful one for description of interactions between shell model clusters, and that the kernels in the RGM are easily obtained from those of the GCM. From the study on the RGM, the effect of the Pauli principle in interactions between clusters is shown to impose the orthogonality condition to the Pauli forbidden states (FS) for the inter-cluster wave functions. And we show that the inter-cluster interaction can be well described by the orthogonality condition model (OCM). Extensions to coupled-channel and multi-cluster problems are given. Discussions on effective potentials between clusters are given. The effect of the almost-forbidden state (AFS) is also discussed.