Proton-neutron pairing effects in medium and heavy mass nuclei

The consistency of the BCS approach in treating proton-neutron pairing correlations is examined. Generalized BCS transformations, which combine proton and neutron states, are used to extract the pairing gap parameter. This procedure gives energy gains due to the inclusion of proton-neutron pairing correlations, but the effect is found to be restricted to small values of the neutron excess $\left(N-Z\right)$.