Correlations and the Dirac structure of the nucleon self-energy

The Dirac structure of the nucleon self-energy in symmetric nuclear matter as well as neutron matter is derived from a realistic meson exchange model for the nucleon-nucleon (NN) interaction. It is demonstrated that the effec ts of correlations on the effective NN interaction in the nuclear medium ca n be parameterized by means of an effective meson exchange. This analysis l eads to a very intuitive interpretation of correlation effects and also pro vides an efficient parametrization of an effective interaction to be used i n relativistic structure calculations for finite nuclei.