Multi-step shell-model method. The nuclei 204pb and 202pb.

Abstract

In this paper we present an extension of the method given in ref. [7] to analyse four- and six-particle systems outside closed-shell cores. The basic idea of the method presented here is to use the two-particle spectrum components as building blocks to describe the four-particle system (the so-called two-phonon states [3, 5, 6]). Once the four-particle spectrum is obtained, we use this spectrum and that of the two-particle system as building blocks to describe the six-particle system. Actually, other partitions are also possible. For instance, one can solve the six-particle system in terms of the five- and the one-particle spectra. We chose the partition mentioned above because we have in mind to analyze the (p, t) experimental data of ref. [8] for which our choice seems natural.