Reaction Dynamics in the Service of Atmospheric Chemistry

Amphithéâtre Pierre Glorieux - CERLA                          Photochemical reaction dynamics in the service of atmospheric chemistry: How the study of fundamental reaction mechanisms can help solve deficiencies in atmospheric models.                                                                         Scott Kable                                                                University of New South Wales Atmospheric models provide the predictive power to assist in the control, regulation and understanding of important issues such as climate change, urban pollution and the recovery of the Antarctic ozone hole. Models, of course, are only as good as the chemical reactions that comprise them. But the atmosphere is incredibly complex – over 2 billion tonnes of organic material, with over a million chemical structures, is emitted to the atmosphere every year. Models are, accordingly, also very complex.  In a recent review of tropospheric chemistry, three significant weaknesses in these models were pointed out: i)       predicting the concentration of OH radicals in forested and polluted regions; ii)     determining the chemical processes that give rise to secondary organic aerosols; and iii)   predicting the concentration of organic acids. We also propose that, with the emergence of the “hydrogen economy”: iv)   understanding the atmospheric balance of H₂ will be important. We are tackling the fundamental chemistry of all four of these issues.  In this seminar, I will explain some of our recent discoveries of new chemical mechanisms that are (or might be) relevant to issues i), iii) and iv) above.