ABSOLUTE YIELDS OF CO, CO2, AND H2CO FROM THE REACTION CH2(X)OVER-TILDE (3)B(1)-LASER FLASH KINETIC SPECTROSCOPY(O(2) BY IR DIODE)

The absolute yields of the stable carbon-containing products CO, CO2, and H2CO formed in the reaction of triplet methylene (X B-3(1) = CH2) with O2 have been determined using a flash kinetic spectrometer. CH2 r adicals were generated by excimer laser photolysis of ketene, and prod uct formation was monitored by time-resolved infrared diode laser abso rption. The reaction was carried out in a static gas cell at room temp erature (T -298 +/- 3 K) with total pressures in the range 1-25 Torr. The measured product yields were as follows: CO, 0.34 +/- 0.06; CO2, 0 .40(+0.09/-0.07); H2CO, 0.16 +/- 0.04. The rate constants for producti on of CO and CO2 were equivalent to the published rate constant for re moval of CH2. Additionally, indirect evidence indicated that the yield of OH is 0.30 +/- 0.05.