Shell-model plus Hartree-Fock calculations for the neutron-rich Ca isotopes

A new method is developed to combine the large-basis shell-model and Hartree-Fock methods. The Hartree-Fock method is used to obtain the absolute uncorrelated binding energies, a starting set of single-particle energies, and the single-particle radial wave functions. The shell model Hamiltonian is modified to remove the monopole terms and these are replaced by Hartree-Fock single-particle energies. The shell model is then used to calculate the ground-state correlation energy and the excited state spectrum. Applications are made to the nuclei ${}^{47–60}\mathrm{Ca}.$ A detailed comparison is made for ${}^{48}\mathrm{Ca}$ including the electron scattering data for ${}^{48}\mathrm{Ca}.$