Ultraviolet Absorption Cross Sections of Cl2O2 between 210 and 410 nm

Article abstract of DOI:10.1021/j100365a033

The ultraviolet and infrared absorption cross of Cl2O2 have been measured.The transient Cl2O2 molecule was produced by using the gas-phase reaction ClO + ClO + M -> Cl2O2 + M.Three independent ClO radical source reactions were used in this study: Cl + O3, Cl + Cl2O, and Cl + OClO.The Cl2O2 UV absorption spectrum was recorded over the range 200-450 nm with a diode array spectrometer over the temperature range 205-250 K.The Cl2O2 infrared absorption spectrum was recorded with a high-resolution Fourier transform spectrometer over the range 500-2000 1/cm.Both spectrometers were optically coupled to a fast flow multipass absorption cell.The UV absorption spectrum of Cl2O2 is a structureless continuum with a peak at 245 nm.The measurable absorption extends out to 410 nm.The UV absorption cross section at the peak of the spectrum, 245 nm, was measured to be (6.5^+0.8_-0.5) X 1E-18 cm².Infrared absorption features centered at 560, 653, and 750 1/cm have been assigned to the Cl2O2 molecule.The present results are compared with other reported UV and IR measurements and the sources of discrepancies are discussed.The role of Cl2O2 in atmospheric chemistry and in particular the Antarctic ozone hole are discussed.