Knowledge Bank

An $Ar+$ laser operating intracavity, coupled with a 1/4 m spectrometer and optical multichannel analyzer, has been used to study both Raman and fluorescence signatures occurring in a $CH4/N2O$ flame. The flame was produced on a raised knife edge burner, which allows probing from the preheat zone through the reaction zone into the burnt gas region. Temperature profiles have been determined from the Stokes Q branch rovibrational spectra of $N2$. Fluorescence profiles of $C2$ have been obtained by excitation of the Swan system using several laser $lines1$. CN fluorescence profiles were obtained by excitation of the violet system at 4545 {\AA}. A multi-band feature has been observed in the 4,200-4, 400 {\AA} region, both in emission and after laser excitation at various lines. Due to the absence of a prominent Q head at 4314 {\AA}, and the presence of stronger fluorescence to the red of 4314 {\AA}, it is unlikely that CH is the source of this fluoresconce. We have tentatively identified this fluorescence system as resulting from NCO radicals produced in this flame.