Characteristic 'shape' of light nucleus. Focus on neutron rich nucleus

Atomic nucleus is a finite quantum many-body system consisted of nucleon, proton and neutron. The image of nucleus is explained by shell model and cluster model. An example of mixture the shell model and the cluster model is 12C (natural parity). The energy level of 12C was calculated by three models such as α + α + p + p + n + n model space (spin orbital force), 3α model (good description of 0+ and 3- state) and coupling of the above two models. The values of the coupling model agreed with the experimental values. Next example, 'sharp' of cluster structure of nucleus was developed by neutron's 'quantum single particle orbital'. Three O+ states were generated in the low exited state of 10Be in order that neutron moved the configurations of (3/2-)2, (1/2+)2 and (1/2-)2 around two α clusters. Main component of 02+ state of 10Be is composed by two neutrons existed in 1/2+, higher shell, and cluster structure of core nucleus developed to 4 fm in order to decrease the orbital energy of 1/2+. We proved the same model was very important for 9Be, 11Be and 12Be. Various interested phenomena of Be isotopes are explained by strange single particle level of neutron and cluster deformation of core nucleus. (S.Y.)