Abstract: Inspired by atmospheric measurements, which have established that atmospheric chemistry occurs in many phases and at interfaces, my group explored the unique reaction environments presented by planetary atmospheres. In this presentation, the special morphological and chemical properties of organic films on aqueous solutions will be discussed with reference to atmospheric aerosols, sea surface microlayers, cloud and fog droplets. The surface of water in aqueous drops and at the sea surface provides a special and unique reaction environment with qualitatively different thermodynamic and kinetic properties from bulk aqueous solutions. Examples from our lab will be presented of chemistry initiated at the water surface leading to increase in the chemical complexity of the organic molecules involved. Solar radiation is the largest source of energy on both the contemporary and early Earth. Multiphase photochemical mechanisms will be discussed by which a-keto acids react in aqueous environments to form organic radicals, which then recombine to form larger, more complex lipids. The generation of such oligomeric organic molecules from smaller precursors is of interest to planetary atmospheric chemistry. The relevance of this chemistry to reactions in the contemporary atmosphere as well as chemistry that may have occurred prebiotically, in the absence of enzymes on ancient Earth, will be discussed.
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