Interfacial reactions between gases and aqueous solutions play an enormous role in our environment. From a microscopic perspective, this is because water molecules, ions, and organic surfactants at the surface of the solution are the first to interact with approaching gas-phase molecules. These “frontier” surface species can momentarily bind to incoming molecules and react with them or block their entry into solution. We can explore the dynamics of these collisions and reactions in vacuum using thick glycerol films and thin water microjets, which are narrower than a strand of hair. I will describe how these techniques can be used to map out the interfacial oxidation of Br- to Br2 by N2O5, catalyzed by ionic surfactants that serve as proxies for sea spray aerosols.
Gilbert Nathanson (University of Wisconsin)