CONICET | Buscador de Institutos y Recursos Humanos

The explanation of halos as well as the description of the behaviour of exotic nuclei, which live a short time and therefore their dynamics is governed by process occuring in the continuum part of the spectrum, requires the introduction of new and powerful models to take into account the complicated interplay among different degrees of freedom that produce weakly bound and esonant states. Among the attemps to describe the structure of rare nuclei the Complex Shell Model method (CXSM) presents the advantage of incorporating on an equal footing bound ingle-particle states as well as resonances and the non-resonant continuum. In the reference [5,6], even the elusive antibound states have been included in the CXSM basis. We plan present a generalization of the Complex Shell Model formalism which includes antibound states in the basis. These states, together with bound states, Gamow states, and the continuum background, represented by properly chosen scattering waves, form a representation where all states are treated on the same footing. Two-particle states are evaluated within this formalism and observable two-particle resonances are defined. The formalism is illustrated in the well known ase of 11Li in its bound ground state and in 70Ca(gs), which is also bound. Both cases are found o have a halo structure. These halo structures are described within the generalized Complex Shell Model. We investigated the formation of two-particle resonances in these nuclei, but no vidence of such resonances was found. 11Li in its bound ground state and in 70Ca(gs), which is also bound. Both cases are found o have a halo structure. These halo structures are described within the generalized Complex Shell Model. We investigated the formation of two-particle resonances in these nuclei, but no vidence of such resonances was found.