Photochemistry of Atmospherically Important Species

316 hF mixing ratios in the stratosphere, and total atmospheric Cl and Br concentrations have been reported. Further measurements have been made of N02, O atoms, and alkanes  

The effects of low concentrations of sulphur dioxide upon the rates of O3 and NO formation in irradiated mixtures of NO2 and air have been investigated, in an effort to determine the reasons for formation of increased tropospheric concentrations of O3 near the plumes of power plants emitting S02. No such effects were observed for SO2 concentrations up to lOp.p.m. when the experiments were repeated with added Cl2 however an increase in the O3 concentration was observed, and a chain-reaction mechanism involving formation of the ClOO species has been suggested to explain the observations. Further two-dimensional modelling calculations of O3 depletion rates have been described. The importance of establishing the fraction F of the removal rate of 0( D) by N2O 

Eichmann, G. Ketseridis, G. Schebeske, R. Jaenicke, J. Hahn, P. Warneck, and C. Junge. Atmos. Environ., 1980, 14, 695. 

Photolysis of O3 in the Hartley bands leads to 02( Ag) production, with 60% formed vibrationally excited,and under atmospheric conditions quenching is found to be a rapid process. Rates of formation of 02( Ag) by this mechanism in the upper atmosphere of Venus have been calculated and compared with those determined by observations of the 02( Ag) emission at 1.27 pm for the values to agree, the previously accepted ozone concentrations would have to be revised upwards by a factor of 10. In the terrestrial atmosphere, the photolysis of 1 6q 1 8q at wavelengths between 170—205 nm could be an important source of odd oxygen in the high stratosphere and mesosphere, as solar radiation not absorbed by discrete 02 features may penetrate these regions and photolyse the minor isotopic constituent (present as 4% of naturally occurring 02).  

Laser-induced fluorescence measurements of atmospheric OH have been carried out now for several years, and shown to be capable of detecting extremely low concentrations of the radical. It has been pointed out however that interference from laser-generated OH could affect the results considerably the wavelength used for OH excitation, 282 nm, generates 0( Z)) from O3 photolysis, and this reacts with H2O to form OH in the troposphere in a time ( 1 ns) which is shorter than the laser pulse width. Calculations and experimental assessments of the importance of this effect have been described. The reaction of OH with CS2 

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