Seminar

Abstract

How gas-phase materials become incorporated with cloud droplets has been an intriguing subject for decades, and considerable work has been done to understand the interactions between closed-shell molecules and liquid water. The interactions between open-shell radical species and the air/water interface of cloud droplets, however, are not well understood. To probe these interactions we used quantum chemistry calculations to predict the energetics of the hydroperoxy radical (HO2) in the presence of a model cloud droplet surface. Our calculations show that it is energetically favorable for the radical to bind at the interface. This configuration and orientation of the radical binding will be discussed as well as the implication for chemistry. Free-energy calculations and molecular dynamics simulations provide some intriguing insight into the partitioning between radicals that are surface-bound and radicals that dissolve into the bulk. This has important ramifications for our understanding of radical chemistry and lends insight into the role that clouds and aerosols play in processing chemistry in the atmosphere.