Perturbation Study on the Reaction of C₂ with N₂ in High-Temperature C₆₀/Ar + N₂ Mixtures

Abstract

The reaction of C2 radicals with nitrogen was studied behind reflected shock waves by time dependent absorption and emission measurements. Mixtures of fullerene C60 highly diluted in argon were shock heated and used as C2 sources. Perturbation of the reaction system by addition of N2 results in changes of C2 absorption and causes strong CN emission. The C2 concentration was quantitatively monitored by ring dye laser absorption spectroscopy at ν = 19 355.60 cm-1. Simultaneously, the time behavior of spectrally resolved light emitted from the shock-heated mixtures was recorded by an intensified CCD camera in the wavelength range 315 nm ≤ λ ≤ 570 nm. By comparing the integrated C2 and CN emission signals for the Δv = 0 progressions, the CN concentration can be determined on the basis of the known C2 concentration and the relative line strengths. The experiments were performed in the temperature range 2896 K ≤ T ≤ 3420 K at pressures 1.68 bar ≤ p ≤ 2.03 bar. Evaluation of C2 and CN concentration measurements lead to the following rate coefficient for the reaction C2 + N2 ⇌ CN + CN: k 3 1.5 × 1013 exp(−21 000 K/T) cm3 mol-1 s-1. The uncertainty in k 3 is expected to be ±50%.

Modeling nitrogen chemistry in combustion

“…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. Only the C + N 2 reaction to form CN + N (R5b) or NCN (R7b) is suciently fast to compete with CH + N 2 (R4).…”

N2-CH4-Ar Chemical Kinetic Model for Simulations of Atmospheric Entry to Titan

“…Nitrogen chemistry and reaction rates at high temperatures have been studied by Park in detail [12,13]. Therefore, nitrogen dissociation and ionization reactions and their rates are taken from recent reviews of Park et al [14][15][16] Hydrocarbon species reactions and their rates are taken from comprehensive reviews of Baulch et al [17,18], Tsang [19], Tsang and Herron [20], Tsang and Hampson [21], NIST chemical kinetics database [22], and journal articles [23][24][25][26][27][28][29][30][31].…”

Studies of the plume emission during the femtosecond and nanosecond ablation of graphite in nitrogen

“…31 Such a proposal appears attractive, both on energetic grounds and because of the obvious correlation between the relative strengths of the CN͑B -X͒ and C 2 ͑d -a͒ emission intensities. It also accords, qualitatively, with the observation ͑Fig.…”