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Chemistry of halogen oxides in the stratosphere

Objective

The aim of this project is to obtain a quantitative understanding of the chemical and photochemical processes involving halogen oxide species which are implicated in ozone depletion in the stratosphere, specially in the polar regions and at mid-latitudes.


The novel chemical schemes associated with this ozone destruction suggest the important role of species such as Cl0, Cl202, 0Cl0, Br0 through a number of reactions, the kinetics and mechanisms of which are not well established. Measurements of rate coefficients, product branching ratios and photochemical parameters are all involved and will be essentially made at low temperatures. The following topics will be covered:

1. Formation and decomposition of the Cl0 DIMER:
low temperature, low pressure kinetic data for the Cl0 + Cl0 + M reaction and kinetic parameters for the thermal and photolytic decomposition reactions of Cl202.

2. Coupling reactions of X0 and R02 radicals:
kinetic and mechanistic data for the reaction Cl0 + Cl0, Cl0 + CH302 and Br0 + H02.

3. Other relevant reactions:
kinetic and mechanistic data for the X + 02 + M association reactions (X = F,Br) and radical reactions involving Cl0x species.

4. Spectroscopic studies:
UV absorption cross sections of Br0, Br0N02, H0Br, Cl03 and IR spectra of Cl202, Cl203.
All these measurements are expected to be achieved through a combination of complementary experimental methods at the different laboratories to ensure high quality and reliability in the data produced. These data will be of first importance for the models both in their interpretation of field measurements and in their predictive capabilities for future ozone depletion.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
Address
Avenue De La Recherche Scientifique 1 C
45071 Orleans
France

Participants (7)

Bergische Universität - Gesamthochschule Wuppertal
Germany
Address
Gaußstraße 20
42097 Wuppertal
Christian-Albrechts-Universität Kiel
Germany
Address
Olshausenstraße 40
24118 Kiel
GEORG-AUGUST-UNIVERSITÄT GÖTTINGEN
Germany
Address
Tammannstrasse 6
D-37077 Göttingen
LINKOEPING UNIVERSITY
Sweden
Address
23,Valla
58183 Linkoeping
MAX-PLANCK-GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V.
Germany
Address
Johann Joachim-becher-weg 27
55020 Mainz
The Chancellor, Masters and Scholars of the University of Oxford
United Kingdom
Address
South Parks Road
OX1 3QZ Oxford
Universität Bremen
Germany
Address

28334 Bremen