UV Absorption Study on the Reaction of Methyl Radicals behind Shock Waves

By using the shock tube technique, the effective decadic molar extinction coefficient ( ε ) of methyl radicals was determined at temperatures between 1400 and 2400 K in the range of the 2 A' 1 – 2 A'' 2 electronic transition between 2100 and 2250 Å. This ε had the maximum value at 2160 Å and decreased with an increase in increase in temperature. The rate constant for the reaction CH 3 +CH 3 except the recombination to ethane was K 5 =9.7 × 10 15 exp (-128 KJ/mol/ R T ) cm 3 /mol s at temperatures between 1600 and 2000 K. The rate constants for the decomposition of ethane were dependent on the density in the range between 2 × 10 -6 and 1.5 × 10 -4 mol/cm 3 .