Semi-empirical effective interactions for the 1s-Od shell
Ground-state binding energies and excited-state energies of nuclei in the 1s-Od shell are analyzed in terms of a variety of two-body interactions. In addition to simple interactions such as the delta and surface-delta, we consider potentials of the finite-range, one-boson-exchange type for the central, tensor, and spin-orbit components of the interaction, with multipole terms added to the central part. The relative importance of these components, together with that of the antisymmetric spin-orbit component, is considered. The antisymmetric spin-orbit component is found to be the least important. Both density-dependent and density-indpendent interactions are considered. Our results favor a density-dependent form for the central and spin-orbit components. We develop a semi-empirical "best-fit" interaction based on a 14-parameter density-dependent two-body potential which reproduces 447 sd-shell binding-energy data to within an rms deviation between experiment and theory of 260 keV. This semiempirical interaction is compared to typical G-matrix interactions as well as to the purely empirical interactions obtained by using two-body matrix elements or Talmi integrals as parameters of the fit. © 1988.