Collective 0 − vibrations in even spherical nuclei with tensor forces

Abstract

The ifJ π = 0 − states of the eight nuclei 16O, 40Ca, 48Ca, 56Ni, 90Zr, 114Sn, 140Ce and 208Pb are computed in the framework of the particle-hole model with the Tamm-Dancoff and random phase approximations. The interaction used is similar to the effective interaction derived by Kuo and Brown and contains central, tensor and spin-orbit components. Coherent τ = 0 and τ = 1 states are obtained and the tensor force is found to give considerable attraction in the τ = 0 modes. However, it is not strong enough to cause a transition to a state with single-particle orbits of mixed parity.