RELATIVISTIC MODELS FOR NUCLEAR-STRUCTURE CALCULATIONS - COMPARATIVE-STUDY OF MEAN-FIELD AND HARTREE-FOCK APPROXIMATION FOR SUPERHEAVY NUCLEI

The relevance of exchange effects for the stability of superheavy nucl ei is examined within a linear QHD-II model by comparing Hartree-Fock with mean-field results. To allow a scan of the complete superheavy re gime the recently developed local density approximation (LDA) for the exchange potential is employed for the Hartree-fock level calculations . It turns out that, while many nuclear properties obtained with the L DA approach differ significantly from the corresponding mean-field res ults, the predictions of the two methods for shell closures are very s imilar. Furthermore, a comparison with a nonlinear variant of QHD-II s hows that many nuclear properties obtained with the LDA in the framewo rk of linear QHD-II are somewhere in-between the corresponding linear and nonlinear mean-field results. This indicates that the LDA exchange partially includes nonlinear contributions, which supports the interp retation of the meson self-coupling as a parametrization of many-body effects.