Study of neutron-rich nuclei via nuclear force and microscopic theory*

Kuo-Kurenciglowa (KK) method is a successful many body perturbation theory to construct the effective interaction for the shell model calculations, but has only been for the model space composed of single major shell. We will then present the Extended Kuo-Krenciglowa (EKK) method which enables us to obtain the effective interaction for multi major shell.

We will further discuss the applications of this effective interaction to the neutron-rich nuclei including the "island of inversion", where excitations beyond N=20 gap is important. Numbers of empirical effective interactions in this area have been proposed. However, not enough experimental information is obtained yet to fix the parameters in those interactions. In this point of view, comparisons to most recent experiments are shown to clarify what features of our microscopic interaction are different from those of empirical one.