Kinetics of Gas Phase Electron—Ion Recombination by NO++e -> N-rO 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, kit 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 changes from 2.3xl0~7 to 1.4x 10-' ion-1 cm3 s~‘. At the lower temperatures kt varies as T-0’7, but as T~l's at the hotter ones. There is evidence that circumstances can be devised in flames, when charged species are produced by chemi-ionization in the reverse of reaction (I), whose rate coefficient is found to be 6.7 x 10'12 exp (-31 900/T) atom-1 cm3 s"1 from 1820 to 2650 K.