Effective interaction derived from the BAGEL approach

Abstract Matrix inversion techniques are used to derive an effective hamiltonian for shell-model calculations, which accounts for correlations outside the shell-model space. It is demonstrated that the BAGEL approach leads to a very powerful tool to account for the effects of large Q -spaces in a reliable way. An energy-dependent formulation yields stable results even for cases which are divergent in the perturbative approach due to the presence of intruder states. A first application employing modern one-boson exchange potentials produces results which are in very satisfactory agreement with empirical data.