Hyperfine structure in the red emission system of NbN

Abstract
A detailed study of hyperfine structure observed in the 0,0 band of the 3Φ (aβ) →3Δ (aβ) system of NbN has shown that the secondary hyperfine effects observed in this structure are not due to a perturbation in the 3Δ state but rather to the presence of a nonnegligible hyperfine effect in the 3Φ excited state. Calculations of the intensity factors corresponding to the observed transitions confirm this hypothesis and give results in excellent agreement with experiment