Pairing Interaction in N=Z Nuclei with Half-filled High-j Shell

The role of L=0 pairing interactions (both T=0 and T=1) in three selected bands with the total isospin T=0 in 22Na, 48Cr and 90Rh nuclei is discussed in the spherical shell model. These bands were selected requiring termination in a most unfavourable way. The investigated effects coming from pairing interactions include the change of nuclear wavefunction, quadrupole properties and state energy. To follow the gradual change of nuclear properties, the investigation is performed in a perturbative approach by defining the Hamiltonian with a variable content of the pairing interaction. It is shown that the pairing does not affect the quadrupole properties, if the energy distance to other close lying states is large. The calculated pairing energy is shown to have a similar spin dependence in these three bands. In addition, the influence of the model space as well as of the residual interaction on the derived pairing energy is discussed.