PARITY INVERSION IN THE N=7 ISOTONES AND THE PAIRING BLOCKING EFFECT

The parity inversion anomaly in the spectra of N=7 isotones is discussed based on contemporary shell-model wave functions. It is shown that the proton-neutron monopole interaction in the mean field has a large effect on the energy gap between the 1/2- and 1/2+ states in Be-11, but not enough to explain the inverted spectrum. We point out that the effects of quadrupole core excitation and pairing blocking are equally important to make the parity inversion in Be-11. It is predicted that He-9 has also a parity inversion in the ground state due to the pairing blocking.