Structure of the helium isotopes He-4-He-8

Ground state wave functions of the halo nuclei He-6 and He-8 have been determined by a genetic algorithm in the framework of the refined resonating group model. The genetic algorithm allows one to apply the underlying variational principle to very complex wave functions and to extract their most important structures in order to give a physical interpretation. The spectrum of the particle unstable isotopes He-A+1(N+1) has been determined from the phase shifts of neutron scattering on the particle stable nuclei He-A(N). Stepwise going on, using the same NN potential in the refined resonating group method bound state and scattering calculation,yielded a consistent description of the nuclei He-4,He-5,He-6,He-7,He-8.