Effects of Spin-Isospin-Interactions on Nuclear Collective Motion

The effects of the tensor force, the most prominent spin-isospin interaction, will be discussed from the viewpoints of the spherical single-particle energies and the correlation beyond single-particle motions. The former point will be started with basic properties of the tensor force, and a new mean-field model will be introduced. It will be shown that single-particle properties, including (sub-)magic gaps and spin-orbit splittings, are varied rather strongly by the tensor force. The effects are not weaker than the effects of the diffuse surface due to neutron skin. An example is presented for the so-called island of inversion, for which the boundary is being modified significantly. The latter point, correlations beyond single-particle motion, leads us to a special importance of the N=Z nuclei such as 56Ni.