Rate constants for the reactions of hydroxyl radical with several fluoroethers by the relative rate method.

Relative rate experiments were used to measure ratios of chemical kinetics rate constants as a function of temperature for the reactions of OH with eight fluoroethers, including CF3OCF2CHF2, CF3OCF2CHFCF3, CHF2CF2OCHF2, CF3CHFCF2OCH2CF3, (CF3)2CHOCHF2, CF2HCF2OCH2CF3, CHF2CF2OCHFCF3, and CF3CH2OCH2CF3. The temperature ranges were about 270-400 K. Each compound was measured against at least two references.

Atmospheric chemistry of CF3OCF2CF2H and CF3OC(CF3)2H: reaction with Cl atoms and OH radicals, degradation mechanism, global warming potentials, and empirical relationship between k(OH) and k(Cl) for organic compounds.

Using FTIR smog chamber techniques, k(Cl + CF3OCF2CF2H) = (2.70 +/- 0.52) x 10(-16), k(OH + CF3OCF2CF2H) = (2.

Measurement and estimation of rate constants for the reactions of hydroxyl radical with several alkanes and cycloalkanes.

Relative rate experiments were used to measure ratios of chemical kinetics rate constants as a function of temperature for the reactions of OH with isobutane, isopentane, 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane, 2,3-dimethylpentane, 2,4-dimethylpentane, 2,3,4-trimethylpentane, n-heptane, n-octane, cyclopentane, cyclohexane, and cycloheptane. The results have been used to calibrate a structure-reactivity rate constant estimation method for k(298 K) which, when combined with previously determined relationships between k(298 K) and the Arrhenius parameters, is capable of determining the temperature dependence accurately. The estimation method reproduces most of the observed rate data within experimental accuracy but appears to fail for 2,3-dimethylbutane, which has an anomalously high rate constant.

Carbon dioxide in the atmosphere: isotopic exchange with ozone and its use as a tracer in the middle atmosphere.

Atmospheric heavy ozone is enriched in the isotopes 18O and 17O. The magnitude of this enhancement, of the order of 100%, is very large compared with that commonly known in atmospheric chemistry and geochemistry. The heavy oxygen atom in heavy ozone is therefore useful as a tracer of chemical species and pathways that involve ozone or its derived products.

Isotopic exchange between carbon dioxide and ozone via O(1D) in the stratosphere.

We propose a novel mechanism for isotopic exchange between CO2 and O3 via O(1D) + CO2 --> CO3* followed by CO3* --> CO2 + O(3P). A one-dimensional model calculation shows that this mechanism can account for the enrichment in 18O in the stratospheric CO2 observed by Gamo et al. [1989], using the heavy O3 profile observed by Mauersberger [1981].