Odd nuclei and single-particle spectra in the relativistic mean-field model

The relation between the single-nucleon spectra of doubly magic nuclei and the excitation energies of the neighboring odd nuclei is investigated within the framework of a relativistic mean-field model. Different levels of approximation (spherical, deformed with time-reversal invariance, without symmetry constraints) are computed and compared. Symmetry breaking, although small, has a substantial effect on separation energies and shell gaps. But energy differences completely within occupied or within unoccupied states are rather robust and can be safely estimated from the mere single-nucleon spectra of the even-even reference nucleus. (C) 1998 Elsevier Science B.V.