Structure description of spherical nuclei

What is a spherical nucleus. The Answer seems to be trivial: The potential energy of a spherical nucleus has a deep minimum at epsilon=0. However, this definition is insufficient. Consider for example, the potential energy of Cd114. This nucleus is considered to be one of the typical spherical nuclei. This potential has a maximum at epsilon=0 and two minima at epsilon = 0.125 and epsilon =0.15. The depth of the minima is about 400keV. Similar results can be received for the potential energy of the Pd-isotopes which have in their spectrum a two-phonon triplet, which is typical for a spherical nucleus. Therefore, it seems useful to define a spherical nucleus in the following way: Either the potential energy of spherical nucleus has a deep minimum at epsilon =0, like in the case of magic or semi-magic nuclei, or the potential energy has two minima at epsilon not equal to 0 and one maximum at epsilon = 0, where the depth of the minima, contrary to the deformed nuclei, is smaller or equal to the energy of the first 2+ state E sub(2+)> approximately equal to Esub(def). (Auth.)