Li9and neutron momentum distributions inLi11in a simplified three-body model

A simple three-body oscillator cluster shell model is proposed as an approximation for wave functions of neutron-rich nuclei, having a (core+2n) structure. The model is applied to the ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ nucleus. With a few free parameters the model reproduces the experimental rms matter radius of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$, as well as the experimental transverse momentum distribution of the ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ nucleus resulting from ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ fragmentation on a carbon target at an energy of 790 MeV/nucleon. The transverse momentum distributions of the neutrons from this reaction have also been calculated without any additional parameters. All geometric parameters of the ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ nucleus are also calculated within the framework of this three-body model.