In the geochemistry subgroup we focus on studying fundamental processes relevant to natural groundwater/soil interfaces. With our experimental approach, which entails second- and third-order spectroscopy, we probe the fluid/solid interface directly, characterizing interfacial electrostatic and chemical properties in real time and under environmentally relevant conditions. Previous work has assessed the thermodynamics of adsorption, surface acid/base behavior, interfacial speciation, and environmental mobility of metal pollutants, antibiotics, and surfactants at the water/fused silica interface and the water/α-alumina interface. More recently we have extended this work to investigate metal ion interactions at the water/muscovite interface, the interfacial redox chemistry of the water/hematite and water/zero-valent iron (ZVI) interfaces, and the acid/base behavior of the water/α-quartz interface.

Selected Publications

“Dendritic Oxide Growth in Zero-Valent Iron Nanofilms Revealed by Atom Probe Tomography”
MD Boamah, D Isheim, FM Geiger
The Journal of Physical Chemistry C, 122, 28225-28232 (2018) and arXiv: 1809-04909 (2018)

“Relative Permittivity in the Electrical Double Layer from Nonlinear Optics”
Mavis Boamah, Paul E. Ohno, Franz M. Geiger, and Kenneth B. Eisenthal
J. Chem. Phys. 148, 222808 (2018), Special Topic Issue on Ions in Water, Editor’s Choice and part of “Most Influential Papers in JCP from 2018-19”

“Second-Order Spectral Lineshapes from Charged Interfaces”
Paul E. Ohno, Hong-fei Wang, and Franz M. Geiger
Nature Communications, 8, 1032 (2017)

“Phase-referenced Nonlinear Spectroscopy of the alpha-Quartz/Water Interface”
Paul. E. Ohno, Sarah A. Saslow, Hong-fei Wang, Franz M. Geiger, and Kenneth B. Eisenthal
Nature Communications, 7, 13587 (2016)