Hyperfine Structure of theBΣ+2State of CN

Abstract

Hyperfine-structure energy formulas are developed for ${}_{}{}^2{}_{}{}^{}\Sigma$ states of diatomic molecules and are used to analyze some of the results of the microwave-optical experiment on the CN molecule described in the preceding paper. For the excited $B{}_{}{}^2{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ state the following hyperfine structure constants are derived: $\left|{\Psi }^2\mathrm{}\right(0\left)\right|=(10.2\mathrm{}\pm 0.2)\times {10}^{24}$ ${\mathrm{cm}}^{-3\mathrm{}}$, ${〈\frac{(3\mathrm{}{cos}^2\chi -1)}{r^3}〉}_{\mathrm{av}}=(7\mathrm{}\pm 2)\times {10}^{24}$ ${\mathrm{cm}}^{-3\mathrm{}}$, and $eQq=(-5\mathrm{}\pm 5)$ MHz. These results are found to be consistent with the valence bond structure: C ≐ N:, in which the unpaired electron occupies the $\sigma$-bond orbital of the molecule.