Dipole strength function inLi11

Abstract

The dipole response of the neutron-rich nucleus ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ is calculated in the random phase approximation and compared with the recent experimental measurement of Coulomb breakup by Kobayashi et al. While th theory predicts a softening of the dipole mode as expected, the response is not sufficiently enhanced to explain the experimental data. This shows the need for a theory that deals with correlations beyond those included in random phase approximation.