Event

-Sea spray droplets are often smaller than the period at the end of this sentence, yet they play an enormous role in our atmosphere by reflecting light and acting as tiny chemical reactors.  These droplets vary dramatically in chemical composition, from a rich biological and organic soup to just salt water.  As a member of the Center for Aerosol Impacts of Chemistry of the Environment, I will describe our efforts to understand two of the most impactful aerosol-mediated reactions: the hydrolysis and chlorination of a nitrogen oxide, N2O5, into HNO3 and ClNO2.  N2O5 forms only at night, but it strongly impacts daytime concentrations of ozone (a pollutant) and hydroxyl radical (the "chemical detergent of the atmosphere").  We use flow reactors, gas-liquid scattering experiments in vacuum, and molecular dynamics simulations to decipher the interfacial mechanisms of these reactions.  Our results show that the surface plays a key role and that "spectator ions" are rarely what they seem: many common ions and surfactants enhance or suppress the hydrolysis and chlorination pathways and open up new ones. 
 

Host: Prof. Marsha Lester