Vibrational diffusion flames from

Temperature-Velocity Correlation Measurements for Turbulent Diffusion Flames from Vibrational Raman-Scattering Data... 

This radiative recombination is observed in flames181,213, electric arcs214, shock tubes194,215,216, and atomic flames192,217-219. In flames and arcs, the emission consists of diffuse bands on a continuum, whereas in atomic flames (the reaction of O with CO at low pressures and room temperature) there is no continuum and clear vibrational structure extends from below 3000 A out to at least 6000 A. The process has not been studied as thoroughly as O+NO, but enjoys the same complexities and uncertainties. 

Emission has been observed [364] from various electronic states of BaCl (C n, A n) from Ba + ONCl and of CaCl (B S, A Yi) from Ca + ONCl in a low pressure diffusion flame experiment. No individual vibrational bands were resolved. For Ca 4- ONCl, the population of the CaCl electronic states was in the order X> A>B, reflecting the increasing energy of the state. However, for Ba + ONCl, the ordering isX>C>A. 

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