GEOC 65 |
| Anne M. Chaka, Computational Chemistry Group, Computational Chemistry Group, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8380, Gaithersburg, MD 20899-8380 |
| Metal oxides such as hematite (α-Fe2O3) play an important role in contaminant sequestration and speciation in groundwater aquifers and soils. A key factor in understanding the reactivity of metal oxides, is how bulk water interacts with the surfaces. Yet, despite considerable experimental and theoretical efforts on the clean hematite surface, little is known regarding the surface structure and even the surface stoichiometry under environmental conditions. The gap between conditions accessible to UHV surface science and what is observed in nature has made it difficult to understand why the hematite (0001) surface reacts with water vapor at a far lower threshold pressure than corundum (α-Al2O3) but yet is much more stable with respect to weathering and solubility. We employ a method of ab initio thermodynamics that enables us to link 0K density functional theory electronic structure and vibrational calculations to finite temperatures and pressures to calculate the free energy of a surface in equilibrium with multiple species in the environment. |
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Interfacial Phenomena: Linking Atomistic and Macroscopic Properties
8:00 AM-11:40 AM, Tuesday, March 30, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |