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The temperature dependence of the UV spectra of the HO2 and CH3O2 radicals

1991; Elsevier BV; Volume: 59; Issue: 1 Linguagem: Inglês

10.1016/1010-6030(91)87062-z

1873-2666

Philip Lightfoot, A.A. Jemi-Alade,

Spectroscopy and Laser Applications

Abstract In view of the current disagreement in the literature over the absolute UV absorption cross-sections of the hydroperoxy radical HO2, the room temperature spectrum of this species has been redetermined relative to the well-established maximum of the spectrum of the methylperoxy radical CH3O2. The results obtained are in good agreement with previous work in this laboratory, with σ(HO2, 210 nm)/σ(CH3O2, 240 nm) = 1.06 ± 0.02, giving σ(HO2, 210 nm) = (4.81 ± 0.49) × 10−18 cm2 molecule−1. In addition, the dependence of the form of the HO2 and CH3O2 spectra on temperature has been determined at temperatures up to 777 K. Simple analytical expressions are presented which allow the cross-sections of HO2 and CH3O2 to be calculated as a function of wavelength and temperature.