Spherical Hartree-Fock calculations with linear-momentum projection before the variation - Part I: Energies, form factors, charge densities and mathematical sum rules

Spherical Hartree-Fock calculations with projection onto zero total linear momentum before the variation are performed for the nuclei He-4, C-12, O-16, Si-28, S-32 and Ca-40 using a density-independent effective nucleon-nucleon interaction. The results are compared to those of usual spherical Hartree-Fock calculations subtracting the kinetic energy of the center-of-mass motion either before or after the variation and to the results obtained analytically with oscillator occupations. Total energies, hole energies, elastic charge form factors and charge densities and the mathematical Coulomb sum rules are discussed.