Cloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the water surface are observed to follow mechanisms that are quite different from those in the gas phase. Having a firm understanding of physical/chemical processes at the molecular level on cloud/aerosol surface will allow for the development to accurate global climate models. This talk will discuss some new physical/chemical processes that occur on cloud/aerosol surfaces. We have studied these processes using high-level electronic structure calculations as well as both classical and Born-Oppenheimer ab initio molecular dynamics simulation. According these studies, we reported the simplest Criegee intermediate (CH2OO) exhibits high reactivity toward the interfacial water, with the reaction times being a few picoseconds, 2-3 orders of magnitude faster than that in the gas phase. The presence of interfacial water molecules induces proton-transfer-based stepwise pathways for these reactions, which are not possible in the gas phase. In addition, formation mechanisms for HONO and HNO3 via the NH3-promoted hydrolysis of NO2 dimer and N2O5 on water clusters/droplets are identified.

New insights into physical chemistry on cloud/aerosol water surfaces

2019 Fall National Meeting

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