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Spring Chemistry 501 Seminar

Title: “Electric Fields, Ion Pairing, and the Salty Aqueous Surfaces”
Speaker: Dr. Heather Allen
Professor of Chemistry and Biochemistry
The Ohio State University

UT Host: Dr. Tessa Calhoun

Abstract: Our oceans are the largest generators of highly saline and organic-rich atmospheric aerosol.  Research in the Allen lab investigates ocean and sea spray aerosol systems to understand interfacial speciation and organization to then inform on atmospheric aerosol, cloud, and marine surface reactivity, correlating to climate change and its contributing uncertainties. Surface selective experiments reveal surface propensity of hydrated ions and ion pairs and generation of electric fields inherent to the ordering of electrical double layers at aqueous surfaces. Magnesium solvent shared ion pairing with sulfate is one example where relatively few ion pairs produce a significant electric field at an aqueous surface. In recent work, we investigate iron(III) hydration and speciation. Lipid and fatty acid – ion binding and surface domain formation is investigated to shed light on trace metal enrichment of the ocean’s sea surface microlayer and of sea spray aerosol surfaces. The surface electric field is measured using a Kelvin probe technique and surface potentiometry using radioactive Americium, a new method being refined in our laboratory. Surface tensiometry, Brewster angle microscopy (BAM), and surface vibrational probes of sum frequency generation (SFG), and infrared reflection absorption spectroscopy (IRRAS) are discussed.

Bio: Professor Heather Allen received her B.S. degree in Chemistry in 1993 at the University of California – Irvine. She remained at UC-Irvine for her graduate studies and received her Ph.D. in Physical Chemistry in 1997 working with Nobel Laureate F. S. Rowland, and Professors D. Blake, J. Hemminger, and B. Finlayson-Pitts. She continued her postdoctoral studies in 1997 at the University of Oregon advised by Professor G. L. Richmond. Dr. Allen began her Professorial career at Ohio State in 2000. She has been recognized for many research accomplishments: Research Innovation Award from Research Corp., NSF CAREER Award, Beckman Young Investigator Award, Alfred P. Sloan Research Fellow Award, Camille Dreyfus Teacher-Scholar Award, Fellow of the American Association for the Advancement of Science (AAAS), Ohio State Distinguished Scholar Award, the Alexander von Humboldt Research Award from Germany, and most recently the Tohoku Forum for Creativity awarded in Japan. In addition, Dr. Allen has been recognized for several mentoring awards over the years including the Ohio State Office of Minority Affairs Mentor Award, an Empowered Woman Award from the City of Columbus, and the American Chemical Society National Award for Encouraging Women into Careers in the Chemical Sciences. She is a Full Professor in the Department of Chemistry and Biochemistry, and in the Department of Pathology. 

Tuesday, March 26 at 3:45pm to 5:00pm

Buehler Hall, 555
1420 Circle Drive, Knoxville, TN 37996

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Linda Sherman

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