N2O Dissociation behind reflected shock waves

The dissociation of N₂O/Ar mixtures, with and withoutadded CO, has been studied by monitoring both infrared and ultraviolet emissions behind reflected shock waves. Initial temperatures ranged from 1850 to 2535°K, and the total concentrations were 1.94–2.40 × 10¹⁸ molecule/cm³. The infrared emission, corrected if necessary for CO, was observed to decay exponentially, and an apparent rate constant K_app was obtained. Addition of CO had no effect upon k_app and all the data can be described by the followingArrhenius parameters (in units of cm³/molecule.sec): log A=?9.31±0.12 and E_A=219.1±5.2 kJ/mole. Ultraviolet emission data, in runs with added CO, indicate that the atomic oxygen concentration reached a constant value at t < 600 μsec for T₀ > 2050°K. Numerical integration of the mechanism allowed comparison of calculated and observed parameters relating to both infrared and ultraviolet data. A consistent fit to these data was obtained with k₁=1.3×10^?9 exp (?238 kJ/RT) and k₂=k₃=1.91×10^?11 exp(?105 kJ/RT). The concentration of atomic oxygen produced by N₂O dissociation is shown to be a sensitive function of k₁ through k₃. Upper limits are also set for the rate constants of the following reactions: