Knowledge Bank

The variation of the electronic transition moment with the r-centroid of the transition $v\prime$ , $J\prime \to$ $v\prime 1$ , $J\prime 1$ is determined from experimental emission line intensities. The theoretical transition probabilities used in the evaluation of experimental data were the rotational line strengths of the symmetric top and Franck-Condon factors, where account has been taken of centrifugal stretching. The relative population density of keV electron impact excited states $v\prime$ , $J\prime$ was calculated in the framework of first Born and dipole approximations and is found to agree with the population density derived from earlier intensity measurements in the electron energy loss spectrum. Results for the electronic transition moment for the 2p $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma u+\to$ 1s $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma u+$ system are compared with a priori theory from the literature. The possibility of falsification of the measurements by perturbations and cascading is discussed.