Review of Rate Constants for the Thermal Dissociation of Dinitrogen Oxide (N2O) and the O(3P) + N2O reaction

Abstract

The rate of the reaction of N₂O with O(³P) was investigated experimentally and by kinetic modelling using Arhenius equations but only over a limited temperature range of 1200 ≤ T ≤ 1400k was applied. Upper limit values of the overall rate constant  for the N₂O + O(³P) reaction were estimated by a statistical technique. These values obtained were about a factor of 10 lower when compared with an overall uncertainty of about a factor of three than those calculated from the recommended Arhenius expressions of previous scientist. The thermal dissociation of N₂O in argon was carried out and investigated by monitoring the formation of O(³P) atoms in the reflected shock regime using Atomic Resonance Absorption Spectro-photometry (ARAS). The total density and N₂O ranges were between (2.6x10¹⁸)- (5.4 x 10¹⁸) molecules cm^-3 and (3.3 x 10¹²) – (7.9 x 10¹⁵) molecules cm^-3 respectively.The values for the bimolecular rate constant derived under low-pressure limit conditions are given by the Arhenius expression: K(T) = (1.18 + 0.16) x 10^-9 exp ( -57820 + 460 cal mol^-1) /RT cm³ molecule ^-1 s^-1 for the temperature range of 1195 ≤ T ≤ 2384k. these results extend the low-temperature range of Atomic Resonance Absorption Spectrophotometry measurements of K₁ by about 200^oc which is very significant in I/T; and the value of the rate constant was extended by more than an order of magnitude. Uncertainties in the Arhenius expression are given at the one standard deviation level and the mean deviation of the experimental data from that predicted by the expression is ± 26%.