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The shell model with the phenomenologic~l effective interaction is applied to study level structures of 2°Ne, Z~Ne, 2~-Nc, 22Na and 24Mg. The full basis in the sd shell is taken in 2°Ne to diagonalize the energy matrices. This example confirms that SUn symmetry and the supermultiplet provide a very good way of truncation. This truncation is used to calculate level schemes of many nuclei beyond 2°Ne. Even though deviations of the effective interaction from the pure Q-Q interaction and the spin-orbit interaction break the SU3 symmetry and the supermultiplct, the main components of calculated wave functions in low-lying energies can be very well labelled by these two symmetries. Generally, good agreement with observations is found. Particularly, the lowest rotational bands are nicely explained. Exceptions are the level structure of 22Na and ½+ in tPO and 2~Ne, which are too low in the calculation, and the K = 2 bandsin 22Ne and 2~'Mg, which are again too low in the calculation.

The structure of the neutron-rich carbon nucleus 16 C is described by introducing a new microscopic shell model of no-core type. The model space is composed of the 0s, 0p, 1s0d, and 1p0f shells. The effective interaction is microscopically derived from the CD-Bonn potential and the Coulomb force through a unitary transformation theory. Calculated low-lying energy levels of 16 C agree well with the experimental values. The B(E2; 2 + 1 → 0 + 1 ) value is calculated with the bare charges. The anomalously hindered B(E2) value for 16 C, measured recently, is well reproduced.