Single-Particle Levels of Nonspherical Nuclei In The Region150<A<190

Abstract

The application of the single-particle model to nonspherical nuclei is reviewed. The band-head ($I=K$) energy data for intrinsic states of predominantly one-quasiparticle character are compiled for odd-A nuclides in the region $150<A<\mathrm{}190\mathrm{}$. The data are analyzed in two steps: first, the rotational and vibrational contributions to the energies are subtracted to give quasiparticle excitation energies; second, single-particle level schemes are fitted to the quasiparticle energies by BCS blocking calculations. The resulting schemes are presented graphically. The single-particle energies and the pairing calculation parameters are made available so that they can be utilized for various purposes in nuclear structure work. As a result of the analysis, we find indications that the zero-point rotational contributions to the band-head energies may have appreciable variations. The level systematics is compared with various single-particle model calculations, assuming local, axially symmetric potentials, and the potential and shape parameters entering are discussed. The potentials used offer satisfactory interpretation of the relevant features of the systematics. The use of a diffuse potential well with proper parameter choices is of significance, particularly for the single-neutron levels. The values of the deformation parameters ${\epsilon }_2$ and ${\epsilon }_4$ (or ${\beta }_2$ and ${\beta }_4$) preferred by the level systematics are compatible with other evidence concerning the nuclear surface shapes.