Chemiluminescent Emission of CO Fourth Positive Bands in Nitrogen Atom/Oxygen Atom/Reactive Carbon Compound Systems. Relation to Chemi-ionization

Emission of the CO Fourth Positive Bands ${\mathrm{(A}}^1{\mathrm{\pi –X}}^1{\Sigma }^{+})$ is observed in the reactions of atomic N/O mixtures with C₂F₄, C₂H₄, C₂H₂, and C₂N₂ at about 300°K and pressures of 1–4 Torr. The N/O/C₂F₄ system, which has been investigated most extensively, produces CO $A^1{\mathrm{\pi –X}}^1{\Sigma }^{+}$ emission which, like the NO⁺ chemi‐ion formation rate, follows [N]³[O] kinetics. The level of excitation extends to at least 10.3 eV above $\mathrm{CO}{\mathrm{(X}}^1{\Sigma }^{+}\text{, υ\hspace{0.17em}=\hspace{0.17em}0)}$ . It is shown that the formation of $\mathrm{CO}{\mathrm{(A}}^1\mathrm{\pi )}$ can be attributed to enhanced formation of excited N₂ and NO molecules in atom‐recombination reactions induced by a reaction intermediate (probably CN), followed by pooling of the energy of an N₂* and an NO* molecule and energy transfer to the reaction product $\mathrm{CO}{\mathrm{(X}}^1{\Sigma }^{+})$ . The transfer reaction can take place before or after the pooling reaction. Formation of $\mathrm{CO}{\mathrm{(A}}^1\mathrm{\pi )}$ in the N/O/C₂H₄ system exhibits the same kinetic dependence on N and O atoms. For the N/O/C₂H₂ system, the observations indicate $\mathrm{CO}{\mathrm{(A}}^1\mathrm{\pi )}$ formation both via the above energy‐pooling mechanism and via the mechanism operative in the O/C₂H₂ reaction [O+C₂O→CO(A ¹π)+CO(X ¹Σ⁺)]. In the N/O/C reactions, the higher vibrational levels of $\mathrm{CO}{\mathrm{(A}}^1\mathrm{\pi )}$ are relatively more populated than in the O/C₂H₂ reaction.