Nonadiabatic Decomposition of N2O in the Deactivation of O(1D) by N2

An extension of a flash‐photolysis method described previously was used to measure the following absolute rate constants (all in liter per mole·sec):

$$\begin{array}{cc}\mathrm{O}{(}^1\mathrm{D)+}{\mathrm{O}}_3\text{→2}{\mathrm{O}}_2& k_2{\text{=2.0±1.0×10}}^{11},\\ \mathrm{O}{(}^1\mathrm{D)+}{\mathrm{N}}_2\to \mathrm{O}{(}^3\mathrm{P)+}{\mathrm{N}}_2& k_{\text{4a}}{\text{=1.3±0.6×10}}^{10},\\ \mathrm{O}{(}^1\mathrm{D)+}\mathrm{Xe}\to \mathrm{O}{(}^3\mathrm{P)+}\mathrm{Xe}& k_{\text{4b}}{\text{=3.5±1.7×10}}^{10},\\ \mathrm{O}{(}^1\mathrm{D)+}\mathrm{Ar}\to \mathrm{O}{(}^3\mathrm{P)+}\mathrm{Ar}& k_{\text{4c}}{\text{∼5×10}}^7.\end{array}$$

The efficiency with which the O(¹D)→O(³P) transition is induced by collisions depends specifically on the added gas. The results for deactivation by nitrogen are discussed in terms of the formation of an N₂O^* intermediate in a high level of vibrational excitation. Dissociation to N₂+O(³P) at this energy level (85.2 kcal) is compared with thermal decomposition of N₂O where predissociation to a state which correlates with O(³P) occurs at a lower energy level (〈ε〉=61.8 kcal).