Improved inverse gap equation and quasiparticle theories of odd and even tin isotopes

The nuclear-structure properties of the odd and even tin isotopes are studied, making use of an improved inverse-gap-equation (IGE) method and the quasiparticle theories. The two-body nuclear force assumed is a realistic potential (or reaction matrix) renormalized for the core polarization, and two cases are considered: (a) the potential of Tabakin, and (b) the reaction matrix of Yale-Shakin. While most types of levels are obtained in good agreement with experiment, others sharply disagree with the data. Only poor agreement with experiment is obtained for the electromagnetic properties of some of the calculated states and for the inelastic electron-scattering form factors. Spectroscopic factors for the one- and two-nucleon transfer reactions are presented and discussed. A warning is given against too much optimism about the indiscriminate applicability of the IGE method. Possible explanations for the difficulties of the method are discussed.