Broadband sum frequency studies of surface-bound organic species relevant to atmospheric oxidation reactions

COLL 379

Andrea B. Voges and Franz M. Geiger. Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208
Biogenic emissions are composed of volatile organic compounds (VOCs) that can react with atmospheric OH and ozone. These gas phase reactions produce partially oxidized organic species that are often surface active. Using the surface-selective nonlinear optical spectroscopy sum frequency generation (SFG) in broadband mode, we studied a partially oxidized VOC, namely menthenol, adsorbed to silica surfaces. Menthenol contains one double bond belonging to an aliphatic C-6 ring. Following the ring-breaking interaction of ozone with menthenol at the surface, we are in the unique position to monitor heterogeneous processes relevant to atmospheric surface chemistry with surface specificity, in real time, and at ambient temperatures.