Hyperfine Structure of the Microwave Spectra of the NO Molecule and the Nuclear Quadrupole Moment of Nitrogen

The frequencies of the magnetic resonance spectrum of the NO molecule has been recalculated by using the new value of spin-orbit coupling constants and by taking the effect of $l$ uncoupling into consideration. The agreement between the theoretical and experimental results is improved over the previous calculation. By combining the magnetic hyperfine and nuclear quadrupole coupling constants the ratio of the quadrupole moment to the magnetic moment of the nitrogen nucleus is obtained. The nuclear quadrupole moment of nitrogen is found to be (0.016\ifmmode\pm\else\textpm\fi{}0.007)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}24}$ ${\mathrm{cm}}^{2}$. The uncertainty of this value is chiefly due to that of the coupling constants rather than to the nature of the method itself.