Knowledge Bank

The 0-0 band of the $b1\Sigma +-X3\Sigma -$ electronic transition of the NF $molecule1$ has been recorded with a Bomem Fourier transform spectrometer and the rotational line intensities have been fitted to theoretical $formulas2$ involving both parallel $(u0)$ and perpendicular $(u1)$ transition moments. The value obtained for the ratio $\mu 1/\mu 0$ is 0.261, with standard deviation 0.004. This result, which corrects previous misstatements in Refs. 1 and 2 that the perpendicular component is stronger, can be combined with measured radiative $lifetimes3$ to give experimental values of $u0$ and $u1$ that will be compared with ab initio $values4,5$.