PARAMETERS FOR OZONE PHOTOLYSIS AS A FUNCTION OF TEMPERATURE AT 280-330 NM

This study was undertaken to obtain the parameters for ozone photolysis in the 280-330 nm region as a function of temperature in the 200-300 K range. The absolute absorption coefficients for O3 were measured at 298, 271, 225, and 206 K and were tabulated at 1-nm intervals over the 250-270 nm wavelength range. Uncertainties in the absorption coefficients range from 2% at room temperature to about 14% at 206 K and mainly fall in the 3-7% range. Pressure of 0.02-100 torr ozone were used, and no pressure effect was observed up to 800 torr N2. The relative 0(1D) quantum yeild resulting from laser pulse photolysis of ozone was measured at 300, 260, and 198 K, in the 280-310 nm region by direct observation of the O(1D) fluorescence at 630 nm. This was the first measurement of the O(1D) quantum yields based on direct observation of O(1D) emission. These measurements were put on an absolute basis by measuring the primary quantum yield of O(3P) at the same temperatures using the O(3P) resonance fluorescence triplet at 310 nm. This was accomplished by examining the time behavior of the O(3P) signal in the presence of an excess of N2, and in the presence of ozone alone. In general, we found that the time dependence for both O(3P) and O(1D) signals were as expected from rate constants in the literature. At room temperature we found about 5 + or - 2% O(3P) formation at 290 nm, and 8 + or - 3% at 270 nm. The implications of the data concerning the detailed photolysis mechanism of ozone and the atmospheric modeling of this process are discussed. (Author)

  • Corporate Authors:

    SRI International

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    Menlo Park, CA  United States  94025-3493

    Federal Aviation Administration

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  • Authors:
    • Davenport, J E
  • Publication Date: 1980-4

Media Info

  • Pagination: 42 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00337232
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: FAA/EE-80-44
  • Contract Numbers: DOT-FA78WA-4263
  • Files: NTIS, USDOT
  • Created Date: Aug 15 2003 12:00AM