Knowledge Bank

The profiles of relative concentration and translational temperature have been measured for the $NH2$ radical in $NH3/02$ flames operating at low pressure using a laser absorption spectroscopy technique. The extremely narrow laser linewidth employed in this study allows absorption spectra to be obtained which are free from the complications that arise when convolution of the absorption line with the laser line or a spectrometer slit function is required. The measured absorption spectra are fit to the Voigt theoretical representation of an absorption line such that the relative number density and translational temperature along with other spectroscopic parameters are evaluated. This type of analysis has been carried out for both resolved isolated rotational absorption transitions as well as unresolved spin-split doublets. Details of this spectral analysis procedure and illustrative results are presented.