Proton-neutron quadrupole interactions: an effective contribution to the   pairing field
  We point out that the proton-neutron energy contribution, for low multipoles (in particular for the quadrupole component), effectively renormalizes the strength of the pairing interaction acting amongst identical nucleons filling up a single-j or a set of degenerate many-j shells. We carry out the calculation in lowest-order perturbation theory. We perform a study of this correction in various mass regions. These results may have implications for the use of pairing theory in medium-heavy nuclei and for the study of pairing energy corrections to the liquid drop model when studying nuclear masses. 
R.Fossion (1), C.De Coster (1), J.E.Garcia-Ramos (1,2) and K.Heyde (1)   ((1) Gent Univ (Belgium), (2) Huelva Univ (Spain))