Calculation of the Magnetic Hyperfine Structure Coupling Constants of NO

A calculation of the magnetic hyperfine structure (hfs) coupling constants of NO has been made using an ab initio configuration interaction wave function built from LCAO-MO-SCF orbitals. The constants predicted by this wave function are in good agreement with experiment for the two constants related to the quantities ${〈\frac{L_z}{r^3}〉}_{\mathrm{av}}$ (constant $a$) and ${〈\frac{\left({sin}^2\theta \right)S^{-}}{r^3}〉}_{\mathrm{av}}$ (constant $d$). The direct calculation of ${〈\frac{(3\mathrm{}{cos}^2\theta -1)S_z}{r^3}〉}_{\mathrm{av}}$ (constant $c$) gives a value which is about 25% less than that predicted by an approximation which implies that unpaired $l$ and $s$ are associated with the same electron. From this calculated value of $c$ the quantity ${〈{\psi }^2\mathrm{}\left(0\right)\mathrm{}〉}_{\mathrm{av}}-\frac{1}{3}c$ (constant $b$) now is found to be about 40 Mc/sec instead of 68.91 Mc/sec which has been previously used by experimentalists.