Study of the spectra and recombination kinetics of alkyl radicals by molecular modulation spectrometry. Part 1.—The spectrometer and a study of methyl recombination between 250 and 450 K and perdeutero methyl recombination at room temperature
Using the technique of molecular modulation spectrometry, the rate constant for methyl radical recombination has been measured to be (4.0 ± 0.9)× 10–11 cm3 molecule–1 s–1 between 250 and 450 K. The rate constant for perdeuteromethyl radicals is identical (within 20 %) at room temperature. With 0.6 nm resolution the effective peak absorption cross-section for methyl radicals at 216 nm is (3.2 ± 0.6)× 10–17 cm2, consistent with an absolute cross-section of (4.2 ± 0.8)× 10–17 cm2. With a resolution of 1.0 nm the observed maximum cross-section for CD3 absorption, 3.0 × 10–17, is consistent with an absolute cross-section of (1.0 ± 0.2)× 10–16 cm2.