Theoretical approaches to modeling interfacial structure and EXAFS data

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:559936

Schenter, G K; McCarthy, M I; Chacon-Taylor, M R ^[1]

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1. Pacific Northwest National Lab., Richland, WA (United States); and others

Understanding the molecular scale processes that control the fate and transport of contaminant metals through the subsurface is a key goal of molecular environmental research. Extended Xray Absorption Fine Structure (EXAFS) spectra is a powerful experimental technique for determining the structure of solvated metal ions at mineral interfaces. The interpretation of these data is aided by theoretical models of the interfacial chemistry and physics. Using ab initio based potential models and classical mechanics simulations, we are able to predict the structure of (M+)aq/mineral interfaces. We will discuss both the development of the ab initio based classical electrostatic potentials for modeling the interaction between molecules and surfaces and the simulation techniques used to model dynamical processes of ions at water/mineral interfaces. This information is then used as input for calculations of the corresponding EXAFS spectra as a function of temperature and surface topology. Theoretical predicted spectra for Na+(H2O)n clusters on MgO (001) will be presented, emphasizing trends in the observed EXAFS spectra with cluster size, temperature, and surface topology (flat surface, edge and corner MgO sites).

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 559936
• Report Number(s): CONF-970443--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
54 ENVIRONMENTAL SCIENCES
ABSORPTION
ENVIRONMENTAL TRANSPORT
INTERFACES
MAGNESIUM OXIDES
METALS
MINERALS
SODIUM COMPOUNDS
SPECTRA
TEMPERATURE DEPENDENCE