Kinetics of gas phase electron–ion recombination by NO++ e–→ N + O from measurements in flames

Abstract

Mass spectrometric measurements of ion concentrations in the burnt gases of flames of either C₂H₂+ O₂+ N₂+ occasionally trace amounts of NO or H₂+ O₂+ N₂ with small additions of C₂H₂ and NO have enabled the rate coefficient, k₁, for electron–ion recombination in reaction (I) NO⁺+ e^–→ N + O (I) to be determined. Such measurements have been made for a wide variety of flame conditions over the temperature range 1820 to 2650 K and indicate that k₁ changes from 2.3 × 10^–7 to 1.4 × 10^–7 ion^–1 cm³ s^–1. At the lower temperatures k₁ varies as T^–0.7, but as T^–1.5 at the hotter ones. There is evidence that circumstances can be devised in flames, when charged species are produced by chemi-inoization in the reverse of reaction (I), whose rate coefficient is found to be 6.7 × 10^–12 exp (–31 900/T) atom^–1 cm³ s^–1 from 1820 to 2650 K.