Unbound exotic nuclei studied via projectile fragmentation reactions

We present a time-dependent model for the excitation of a nucleon from a bound state to a continuum resonant state in the neutron-core potential. The final state is described by an optical model S-matrix so that overlapping resonances of any energy as well as deeply bound initial states can be considered. Due to the coupling between initial and final states the neutron-core free particle phase shifts are modified, in the exit channel, by a small additional phase. The model allows to extract structure information from data obtained in projectile fragmentation reactions of a borromean nucleus on a light target. Some results relative to the study of 13Be are presented. (orig.)