In order to discuss atomic hyperfine-structure effects not exhibited by restricted Hartree-Fock wave functions, a "polarization wave function" is introduced. This wave function, designed to include core polarization, is defined to be that configuration-interaction function which includes the restricted Hartree-Fock function plus all symmetry-allowed configurations differing therefrom by one spatial orbital. Good approximations to polarization wave functions are reported here for the ground states of B, C, N, O, and F. The resulting magnetic hyperfine-structure parameters are in better agreement with experiment than in previous ab initio calculations, being subject to between 25 and 45% error in the spin-density contributions and to less than 2% error in the other terms. The value of $〈r^{-3\mathrm{}}〉$ is found to depend significantly upon the operator in which it appears, and this dependence causes us to conclude that spin densities for B and C cannot be deduced from available experimental data. Our calculations are also used to provide improved values for the nuclear magnetic-dipole moment of ${\mathrm{C}}^{11}$ ($\pm 0.997 {\mu }_N$) and for the nuclear electric-quadrupole moments of ${\mathrm{B}}^{10}$ (0.0804 b), ${\mathrm{B}}^{11}$ (0.0386 b), ${\mathrm{C}}^{11}$ (±0.0322 b), and ${\mathrm{O}}^{17}$ (-0.0256 b).

• Received 22 July 1968

DOI:https://doi.org/10.1103/PhysRev.176.49