Intensities inΠ2−Σ2Transitions in Diatomic Molecules

Simple intensity expressions for ${}_{}{}^2{}_{}{}^{}\Pi -{}_{}{}^2{}_{}{}^{}\Sigma$ and ${}_{}{}^2{}_{}{}^{}\Sigma -{}_{}{}^2{}_{}{}^{}\Pi$ transitions in diatomic molecules have been developed for cases in which the ${}_{}{}^2{}_{}{}^{}\Pi$ state is intermediate between Hund's case (a) and case (b), by specializing the general formulas given by Hill and Van Vleck. Numerical values have been worked out for all branches in typical ${}_{}{}^2{}_{}{}^{}\Pi$ cases, for low values of $J$.