Spectroscopic Study of the Chemiluminescent Reaction O + CCO

Further spectroscopic studies of the chemiluminescence from oxygen atom–acetylene and oxygen atom–carbon suboxide flames are reported. The reaction¹⁸ O + CC¹⁶O→C¹⁸O + C¹⁶O results in the emission of Fourth Positive bands by both C¹⁸O and C¹⁶O with comparable intensities, suggesting that the intermediate OCCO exists for at least several vibrations. Some bands in the $d^3{\mathrm{\Delta \to X}}^1{\Sigma }^{+}$ system are identified. Partially resolved rotational structure of the Fourth Positive bands show irregular intensities which are interpreted as strong emission from perturbed rotational levels. It is concluded that the reaction forming excited CO in hydrocarbon flames populates the $A^1{\mathrm{\Pi ,\; d}}^3{\mathrm{\Delta ,\; e}}^3{\Sigma }^{-}{\mathrm{,\; I}}^1{\Sigma }^{-},\mathrm{and}{\mathrm{a\prime }}^3{\Sigma }^{+}$ states of CO at comparable rates. Possible reactions of the metastable CO molecules are suggested.