Air broadening coefficients for the ν3 band of hydroperoxyl radicals

- Mid-infrared absorption spectra of HO2 measured in the presence of N2 or O2.
- The air broadening coefficients of HO2 were determined in the ν3 band.
- The dependence of air broadening on rotational states is discussed.

Using mid-infrared laser absorption spectroscopy, we investigated the room-temperature pressure broadening coefficients for hydroperoxyl radicals (HO2) in nitrogen and oxygen over the 1060.0-1065.5 cm−1 range of the ν3 band. The HO2 radicals were produced by flash photolysis of a chlorine/1,4-cyclohexadiene/oxygen mixture. The 20 measured absorption profiles were analyzed with Voigt functions. Air broadening coefficients were estimated from the nitrogen- and oxygen-broadening results and compared with previous results. We discuss the dependence of air broadening on rotational states.