Effective interaction of protons and neutrons in the subshells

Abstract

The effective interaction of protons and neutrons in the 2 p 1 2 −1 g 9 2 subshells is determined from energy levels of five N = 50 nuclei, four N = 49 nuclei and the N = 48 nucleus 86 Sr. Charge independence is imposed by using Pandya relations between particle-particle (proton-proton) and particle-hole (proton-neutron) two-body matrix elements. Isospin purity of isobaric analogue states is discussed, and residual Coulomb energies are extracted. The calculated energy levels of 92 Tc and 93 Ru, not included in the fit, are also in good agreement with experimental data. Binding energies of all nuclei considered are nicely reproduced. Applying the results to neutron-neutron effective interaction we find that only the 6 + , 8 + , 4 − and 5 − levels of doubly even N = 48 nuclei are reproduced. Apparently, the 0 + , 2 + and 4 + levels are strongly mixed with configurations outside our model space.