Molecular Chirality and Cloud Activation Potentials of Dimeric α-Pinene Oxidation Products

摘要

The surface activity of ten atmospherically relevant α-pinene-derived dimers having varying terminal functional groups and backbone stereochemistry is reported. We find ～10% differences in surface activity between diastereomers of the same dimer, demonstrating that surface activity depends upon backbone stereochemistry. Octanol-water (K_(OW)) and octanol-ammonium sulfate partitioning coefficient (K_(OAS)) measurements of our standards align well with the surface activity measurements, with the more surface-active dimers exhibiting increased hydro- phobicity. Our findings establish a link between molecular chirality and cloud activation potential of secondary organic aerosol particles. Given the diurnal variations in enantiomeric excess of biogenic emissions, possible contributions of such a link to biosphere:atmosphere feedbacks as well as aerosol particle viscosity and phase separation are discussed.