Measurements of Line Strengths in the HO2 ν1 Overtone Band at 1.5 μm Using an InGaAsP Laser

Article abstract of DOI:10.1021/j100170a022

We report the first observation of resolved rotational-vibrational overtone (2ν₁) absorptions of the hydroperoxyl radical (HO2) in the 1.5-μm region, using two-tone frequency modulation spectroscopy (TTFMS) with an InGaAsP laser diode and White-cell optics.Photolysis of Cl2/H2/O2 mixtures was used to produce the HO2, and the concentration was determined by modulated-photolysis UV absorption spectroscopy.The line center absorption cross sections for the strongest line ranged between 1.3x10^-20 and 10x10^-20 cm² molecule^-1 under Doppler-limited conditions.For the strongest line corresponds to an integrated line strength S of 1.6x10^-21 cm² molecule^-1cm^-1, a line strength of the same order of magnitude as lines previously observed in the relatively weak ν₁ fundamental.