Chemiluminescent emission of CO fourth positive bands in nitrogen atom/oxygen atom/reactive carbon compound systems.*1 Relation to chemi-ionization

Emission of the CO Fourth Positive Bands (A ₁II-X ¹Σ¹) is observed in the reactions of atomic N/O mixtures with C₂F₄, C₂H₄, C ₂H₂, 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 ¹II-X ¹Σ⁺ emission which, like the N0⁺ chemi-ion formation rate, follows [N]³[O] kinetics. The level of excitation extends to at least 10.3 eV above CO(X ¹Σ ⁺, v = 0). It is shown that the formation of CO(A ¹II) 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 CO(X ¹σ ^-). The transfer reaction can take place before or after the pooling reaction. Formation of CO (A ¹II) in the N/O/C₂H ₄ system exhibits the same kinetic dependence on N and O atoms. For the N/O/C₂H₂ system, the observations indicate CO(A ¹II) formation both via the above energypooling mechanism and via the mechanism operative in the 0/C₂H₂ reaction [O+C ₂O→CO(A ¹II)+ CO(X ¹Σ¹)]. In the N/O/C reactions, the higher vibrational levels of CO(A ¹II) are relatively more populated than in the O/C₂H₂ reaction.