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Chemistry Seminar Series 291 (11/17/17)

Date: 
November 17, 2017 - 3:00pm

Richard Saykally, Ph.D., University of California, Berkeley

Abstract:

The behavior of ions at aqueous interfaces has been a subject of much controversy for over a century. By exploiting the strong charge-transfer-to-solvent (CTTS) resonances of selected anions in aqueous electrolytes, their adsorption properties have measured by deep UV-SHG spectroscopy methods for both air/water and graphene/water interfaces. Temperature and concentration dependences determined by both experiment and computer simulations for the air/water case reveal that the strong interfacial adsorption observed for weakly hydrated ions is enthalpically driven by hydration forces and impeded by a novel entropy effect ( capillary wave suppression). Extension of this approach to the water-graphene interface reveals a surprising similarity to the air-water case, albeit with very different mechanistic details. Our recent development of a broadband deep UV SFG spectroscopy technique has produced detailed CTTS spectra of interfacial ions, for which comparisons with bulk CTTS spectra provide additional new insights. 

Reference: D. L. McCaffrey, S. C. Nguyen, S. J. Cox, P. L. Geissler, H. Weller, A. P. Alivisatos, and R. J. Saykally, “Mechanism of ion adsorption to aqueous interfaces: Graphene/water vs. air/water”, PNAS, Early Edition, (2017). 

Contact Information

Name: 
Son Nguyen
Title: 
Assistant Professor
Address: 
5200 North Lake Rd.
Merced, CA 95343
United States
Address: 
5200 North Lake Rd.
Merced, CA 95343
United States