Hyperfine structure ofN2(BΠg3andAΣu +3): OscillatoryJdependence of theΠ0, 13hyperfine structure

Laser-induced fluorescence on a beam of metastable ${\mathrm{N}}_2$ ($A{}_{}{}^3{}_{}{}^{}\Sigma _u^{ +}{}_{}{}^{}$) molecules has been used to study the hyperfine structure of the (10,6) band of the ${\mathrm{N}}_2$ ($B-A$) transition. The hyperfine structure of the $B{}_{}{}^3{}_{}{}^{}\Pi _0^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}\Pi _1^{}{}_{}{}^{}$ states was found to have an unusual, oscillatory $J$ dependence. This was explained by perturbation theory, and hyperfine-structure constants for the $B$ state were derived from a data fit. At the same time results from earlier, less-direct experiments on the $A$-state hyperfine structure were confirmed and extended.