A redundancy-free approach to the use of correlated bases in the truncation of large shell-model eigenproblems

In this paper we describe a method for solving shell-model problems in a severely truncated space spanned by correlated states. The method is based on a partition of the full configuration space in orthogonal subspaces, in which exact shell-model calculations can be done. The method allows a practically exact description of the low-energy spectroscopic properties of nuclei, as exemplified both in a test calculation involving a schematic pairing Hamiltonian and in calculations for systems of neutrons and protons in which a realistic effective interaction derived from the Bonn-A potential is used.