The reaction of O(1D) with CH4

The room‐temperature photolysis of N2O (10–100 torr) at 2139 Å to produce O(1D) has been studied in the presence of CH4 (10–891 torr). The reactions of O(1D) with CH4 were found to be The method of chemical difference was used to measure the rate constant ratio k4/(k2 + k3), where reactions (2) and (3) are The CH3 radicals produced in reaction (4) react with the O2 and NO produced in reactions (2) and (3). Thus, near the endpoint of the internal titration, ϕ{C2H6} gives an accurate measure of k4/(k2 + k3). For the translationally energetic O(1D) atoms produced in the photolysis, k4/(k2 + k3) = 2.28 ± 0.20. However, if He is added to remove the excess translational energy, then k4/(k2 + k3) drops to 1.35 ± 0.3.