Structure of the helium isotopes4He–8He

Ground state wave functions of the halo nuclei ${}^6$He and ${}^8$He 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 ${}^{A+1\mathrm{}}$He${}_{N+1\mathrm{}}$ has been determined from the phase shifts of neutron scattering on the particle stable nuclei ${}^A$He${}_N.$ Stepwise going on, using the same $\mathrm{NN}$ potential in the refined resonating group method bound state and scattering calculation, yielded a consistent description of the nuclei ${}^{4,5,6,7,8}$He.