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Science at the Edge/Interdisciplinary Physics Seminar Friday September 27, 2013 Friday at 11:30 a.m., RM 1400 Biomedical and Physical Sciences Bldg Ions, lipids, and water at the air-aqueous interface: Organization and electric fields Heather C. Allen The Ohio State University Depts. of Chemistry and Biochemistry Abstract Motivated by atmospheric aerosol chemistry of marine and urban regions, and biophysical applications related to lung lining and biomembranes, monovalent and divalent cations and anions were investigated using phase sensitive sum frequency generation (PS-SFG) spectroscopy to understand the surface propensity and availability for reaction at water surfaces. Ion valency, polarizability, size, shape, and identity of the counterion are critical factors in considering ion organization and subsequent changes in interfacial electric field at the air water interface. Phospholipids and fatty acids were also studied using both SFG and Brewster angle microscopy (BAM). Head group differences, especially with regard to hydrogen bonding capability and extent, are discerning factors for surface organization and shape distinction at the water surface. [cid:[log in to unmask]] Shawna Prater / Secretary Astrophysics Group Michigan State University 567 Wilson Road, Room 3261 Biomedical Physical Sciences Bldg East Lansing, MI 48824-2320 Ph: (517) 884-5601 Fax (517) 432-8802 [log in to unmask]<mailto:[log in to unmask]>, [log in to unmask]<mailto:[log in to unmask]>