Oxygen versus Iron Terminations in Hematite Basal Surfaces: STM imagin in air and in aqueous solutions.
EMSL Project ID
2285a
Abstract
This project will focus on determining the surface structure of hematite basal planes in aqueous solutions. Prior to this writing this proposal, we have been imaging hematite surfaces in solution and air using scanning tunneling microscopy (STM) and modeling the surface using a resonant tunneling (RT) model (e.g., Schmickler and Tao, 1997). This model easily allows the inclusion of solvent affects on the redox properties on the calculated STM images, thus allowing us to interpret the meaning of the STM data as well as extracting experimental data, such as the Marcus reorganization energy of the surface sites and the redox potentials. We have been collaborating with a research scientist at EMSL, Kevin Rosso, who is calculating some of the Marcus reorganization energies (which are key to the RT model) for a variety of hematite surface structures. Dr. Rosso has calculated reorganization energies for iron and oxygen terminations of the surface, both with varying degrees of water adsorption. Our goal for this project is to meet and discuss the details of the calculations as well as perform further STM experiments to help test applicability of the RT model. Meeting with Dr. Rosso will serve two functions: our university does not have the computer resources to do these types of calculations, so we will get a chance to actually see the calculations being performed. This in turn will enable us to discuss the calculations with Dr. Rosso at a level of detail that we would be unable to achieve otherwise. This will be invaluable to the productiveness of the project, as well as a learning experience for the graduate student making the trip, Andrew Stack.
Project Details
Project type
Exploratory Research
Start Date
2003-02-03
End Date
2004-02-04
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Eggleston CM, AG Stack, KM Rosso, S Higgins, A Bice, S Boese, RD Pribyl, and JJ Nichols. 2003. "The Structure of Hematite (001) Surfaces in Aqueous Media: Scanning Tunneling Microscopy and Resonant Tunneling Calculations of Co-Existing O and Fe Terminations." Geochimica et Cosmochimica Acta 67(5):985-1000.