The atomic-beam magnetic-resonance technique has been used to extend the hyperfine-structure and $g$-value results of Smith and Spalding to all five members of the $4f^{4}6s^2{}_{}{}^5{}_{}{}^{}I$ ground multiplet of ${}_{}{}^{143,145}{}_{}{}^{}\mathrm{Nd}$. The eigenvectors derived by Conway and Wybourne by fitting the excitation energies are reasonably consistent with the new data. The extent to which the hfs is affected by small components in the eigenvectors is investigated. Empirical values for the radial integrals that appear in the hyperfine structure are compared with predictions based on nonrelativistic Hartree-Fock and on relativistic Hartree-Fock-Slater calculations. The empirical value found for the dipole integral least susceptible to distortion by configuration interaction is within (1-3)% of the value calculated relativistically. Differences between theory and experiment are substantial for some of the other integrals, however. The values of the electric-quadrupole moments of ${}_{}{}^{143,145}{}_{}{}^{}\mathrm{Nd}$ are found to be -0.56(6) b and -0.29(3) b, respectively.

• Received 19 June 1972

DOI:https://doi.org/10.1103/PhysRevA.6.1772