Theory of the Hyperfine Structure of NO Molecule

The theory of the hfs of the NO molecule due to the magnetic moment and the electric quadrupole moment of the N nucleus is worked out. Assuming that the electron which is rotating around the molecular axis is in a pure $p$ state, some relations between coupling constants are derived and were found to agree with experimental relations. Hund's case (a) was taken as a starting point, but the actual deviation from case (a) was found to be not negligible and was also explained satisfactorily. The formula for the nuclear electric quadrupole effect was derived for Hund's case (a) and also for a general coupling case. This electric quadrupole effect was found to be different for $\Lambda$-type doublet states. The difference appears for every coupling case including Hund's case (a). The agreement between theory and experimental results is quite satisfactory.