Pseudo-SU(2) symmetry and a low energy limit of the Dirac equation with the Woods-Saxon potentials

A structure of the Woods-Saxon deformed mean-field Hamiltonian adapted to t he nuclear Dirac equation is discussed. The underlying SU(2) symmetries of the Hamiltonian are reviewed together with their consequences for the behav ior of the single-nucleon spectra. This brings up a strong motivation for i ntroducing the realistic Woods-Saxon parametrisation in such a way that the position-dependent effective mass, an extra linear momentum potential and other features are directly modeled. It is demonstrated that the relatively low values of the effective mass in the nuclear interior do not cause any incorrect level-density problem close to the Fermi level. Moreover, an over -all correct spreading of the single-particle levels over a large energy sc ale and a very good single-particle level order can be obtained. The corres ponding preliminary calculation results are illustrated.