Kinetics of the reaction of Ga atoms with O2
In: Shock Wave Symposium
Buchaufsatz / Kapitel / Fach: Maschinenbau
The reaction of Ga + O2 was studied with mixtures containing 13 - 23 ppm Ga(CH3)3 and 200 - 2895 ppm O2 behind reflected shock waves at temperatures between 1290 and 2320 K and pressures of about 150 and 370 kPa by applying atomic resonance absorption spectrometry for time-resolved measurements of Ga atoms at 403.299 nm. For the simulation of the experiments additional information about the trimethyl gallium decomposition was necessary. Therefore, experiments with 2 to 20 ppm Ga(CH3)3 were performed between 1100 and 1560 K at pressures of about 160 and 400 kPa. Two reaction channels were found for the reaction of Ga atoms with O2, the recombination reaction Ga + O2 +M -> GaO2 +M k1a = 1012.95+-0.41 exp(+12400+-1367 K / T) cm6 mol-2 s-1 is dominant at temperatures T < 1600 K, the reaction Ga + O2 -> GaO + O k1b = 1014.57+-0.36 exp(-12460+-1535 K / T) cm3 mol-1 s-1 is the main reaction channel at T > 1600 K.