Local density theory of electronic structure, binding energies and x-ray absorption near edge spectra in metal compounds

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:7183119

Guo, Jun

Over the past two decades, the local density (LD) theory has become a feasible method of satisfactory accuracy for ground state properties of atoms, molecules, metals, semiconductors, surfaces and defects. The first part of this dissertation is an application of this theory to electronic structure and binding energies in transition metal systems using a discrete variational method. A basis optimization procedure was tested and adopted in the study of isolated Ni cluster. The LD results using the optimized bases gave a satisfactory description of the Ni clusters. The response of charge density of an Ni{sub 4} tetrahedron to a simple covalent probe molecule H{sub 2} was investigated using Bader's topological density analysis. It was a first application of this analysis to a transition metal cluster interacting with a covalent molecule. The chemisorption of C{sub 2}H{sub 2} on s simulated Ni(111) surface was studied using the embedded cluster technique. It provided a good semiquantitative description description of a strongly coupled site suggested from Electron Energy Loss Spectroscopy data. The X-ray Absorption Near Edge Spectra (XANES) contain valuable information on electronic structure of the absorbing atom and its interaction with near neighbors, besides the structure data found in the extended absorption region. A final state relaxation model was proposed and used to generate the final state potentials beginning from LD ground states. L-edge XANES of Pt{sub n} clusters were modeled and found to be sensitive to the cluster geometry. The U M-edge in UO{sub 2} and UCl{sub 4} and the Cu K-edge in La{sub 2}CuO{sub 4}, Cu{sub 2}O, CuO, KCuO{sub 2} were calculated and found to be in quantitative agreement with experiment. From the quantitative comparison of calculated and measured polarized Cu K-edge XANES in La{sub 2}CuO{sub 4}, shakeup features were identified and assigned to Cu 3d {yields} 4p transitions based on the proposed relaxation model.

• Research Organization: Northwestern Univ., Evanston, IL (United States)
• OSTI ID: 7183119
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
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Nuclear Reaction
Radiometric & Radiochemical Procedures
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74 ATOMIC AND MOLECULAR PHYSICS
ACTINIDE COMPOUNDS
ALKALI METAL COMPOUNDS
ALKENES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
CHLORIDES
CHLORINE COMPOUNDS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
COPPER COMPOUNDS
COPPER OXIDES
DATA
ELECTRON DENSITY
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
ETHYLENE
EVALUATION
EXPERIMENTAL DATA
GROUND STATES
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROGEN
INFORMATION
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MATHEMATICAL MODELS
METALS
MILLER INDICES
NICKEL
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
RARE EARTH COMPOUNDS
SEPARATION PROCESSES
SIMULATION
SORPTION
SPECTRA
THEORETICAL DATA
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
URANIUM CHLORIDES
URANIUM COMPOUNDS
URANIUM OXIDES
VARIATIONAL METHODS
X-RAY SPECTRA