Determination of Pathways in Chemical Reaction Systems: An Algorithm and its Application to Stratospheric Chemistry

Dr. R. Lehmann

(Alfred-Wegener-Institut für Polar- und Meeresforschung, Potsdam)

Mittwoch/Wednesday, 2007-4-25 16:15, PN 114

Eugene-Paul-Wigner Gebäudes (Physik-Neubau), Hardenbergstr. 36, 10623 Berlin

Abstract

Numerical models of increasing complexity have been created in order to simulate chemical processes. The growing number of chemical species and reactions included in such models provides the opportunity of a better approximation of reality. However, at the same time, it becomes more difficult to understand the complicated interplay of the processes involved. This motivates the development of automated analysis tools. A typical question is: How, i.e. by which reaction sequences, is a certain species of interest produced (or destroyed)? An algorithm for the automatic determination of such reaction sequences (pathways) will be presented. Under the assumption that a chemical reaction system is given and reaction rates are known, the algorithm constructs all significant pathways and assigns a rate (flow of molecules) to each of them.

The algorithm has been applied to determine catalytic ozone destruction cycles and methane oxidation pathways in a system of approximately 150 reactions, describing the chemistry in the Earth"s stratosphere.