Ab initio chemical kinetics for the reactions of N2 with singlet and triplet C2O radicals

Modeling nitrogen chemistry in combustion

“…The reactions of both triplet and singlet methylene ( 3 CH 2 , 1 CH 2 ) with N 2 have been shown to have too high barriers to contribute to prompt NO formation [1,24,58]. Also, the C 2 O + N 2 reaction, discussed in several publications [5962], has a prohibitively high barrier [63]. The C 2 + N 2 reaction (R6) could be a candidate [64,65], but the low C 2 concentration, typically two orders of magnitude below the CH concentration in premixed ames [66], prevents this step from being signicant.…”

The effect of benzene on the structure of low-pressure premixed H2/CH4/CO-air flames and related NO formation at different equivalence ratios

“…Assumptions on additional prompt NO radical precursors, other than CH, such as ketenylidene (C2O), singlet or triplet CH2, have also been made in literature [22,23,27,29] to explain and reduce the discrepancies between measurements and predictions. However, later theoretical studies showed that the energy barriers of the reactions involving both, triplet and singlet CH2 [30] and C2O [31], with N2 were too high contribute to prompt NO formation. Therefore, further investigation is required when larger hydrocarbons are present in the fuel, especially to address the interactions between fuel oxidation and NO formation chemistry.…”

The story of NCN as a key species in prompt-NO formation

“…1,3 CH 2 + N 2[54][55][56], C 2 + N 2[57,58], and C 2 O + N 2[49,59,60] appear to exhibit high activation barriers or result in low net fluxes due to low concentrations of the relevant intermediates under most flame conditions[35]. Both reactions, C 2 O + N 2 → NCN + CO and C + N 2 (+M) → NCN (+M), have been discussed to feed into the NCN radical pool[35,44,49,59], but a detailed inspection of the related potential energy surfaces showed that they cannot compete with the CH + N 2 reaction.…”

“…Both reactions, C 2 O + N 2 → NCN + CO and C + N 2 (+M) → NCN (+M), have been discussed to feed into the NCN radical pool[35,44,49,59], but a detailed inspection of the related potential energy surfaces showed that they cannot compete with the CH + N 2 reaction. Ab initio calculations performed by Zhu et al[60] on the C 2 O + N 2 reaction gave activation barriers of 253…”