Symmetry Specific Study of Ozone Isotopomer Formation

The unusual isotope effect in the formation of the ozone molecule is not yet understood, even 25 years after its discovery. Furthermore, the experimental database is still unsatisfactory, particularly with regard to application of the heavy oxygen from ozone as an atmospheric tracer. To close a gap in the existing record, a high-resolution diode laser based absorption spectrometer was improved, essentially by the use of a gold-coated astigmatic mirror multipass cell and a calibrated confocal Fabry-Perot etalon. All atmospherically relevant, i.e. the simply 17O or 18O substituted ozone isotopomers could thereby be quantified. Precision in the measurement of the isotope abundance was improved to 0.3%. Systematic errors in earlier investigations were identified and minimized in the present measurements. Relative to the reaction 16O + 16O16O -> 16O16O16O, the rate coefficients of the channels 16O + 16O17O -> 16O16O17O and 16O + 17O16O -> 16O17O16O were determined to be 1.292 ± 0.019 and 1.005 ± 0.010, and those of the channels 16O + 16O18O -> 16O16O18O and 16O + 18O16O -> 16O18O16O were found to be 1.426 ± 0.034 and 1.007 ± 0.013. Thus, the direct connection between the rate of ozone formation and the enthalpy of the isotope exchange reaction is confirmed. Contrary to earlier assumptions, the analysis of a sample from a laboratory simulation further shows that the isotope transfer from ozone into carbon dioxide does not exhibit an isotope anomaly, at least under laboratory conditions. This apparently confirms the unique character of the ozone molecule.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Heidelberg

Year

2005

Author dc:creator

• Tuzson, Bela

Contributors dc:contributor

• Janssen, Christof

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/5523

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:5523