Ab initio studies of the electronic structure and geometry of UF/sub 5/ using relativistic effective core potentials
Ab initio calculations on the low-lying electronic states of UF/sub 5/ are presented using a relativistic effective core potential (ECP) for uranium and a nonrelativistic ECP for fluorine. The ground-state geometry of UF/sub 5/ was optimized at the SCF level using a double-zeta quality Gaussian basis set. Without spin-orbit coupling the square pyramidal structure (C/sub 4v/) was calculated to be 1 kcal/mol lower than the trigonal bipyramid (D/sub 3h/), which was subject to a Jahn-Teller distortion. Inclusion of spin-orbit effects reversed the ordering with the D/sub 3h/ structure 1 kcal/mol lower than the C/sub 4v/. The two geometries are connected by a monotonic C/sub 2v/ path, so that UF/sub 5/ will be fluxional. The ramifications of this fluxional behavior are considered. Improved virtual orbital calculations show that UF/sub 5/ has a series of weak low-lying (2 - 15 x 10/sup 3/ cm/sup -1/)f-f transitions. The results of the photofragment spectra of UF/sub 6/ are discussed in light of these calculations. 44 references, 7 figures, 7 tables.
- Research Organization:
- Los Alamos Scientific Lab., NM
- OSTI ID:
- 5878679
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 101:18
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
URANIUM FLUORIDES
STRUCTURAL CHEMICAL ANALYSIS
CALCULATION METHODS
CHEMICAL BONDS
ELECTRIC POTENTIAL
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
GEOMETRY
GROUND STATES
INFRARED SPECTRA
L-S COUPLING
MATHEMATICAL MODELS
NUMERICAL SOLUTION
TABLES
ACTINIDE COMPOUNDS
COUPLING
DATA
DATA FORMS
ENERGY LEVELS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
INTERMEDIATE COUPLING
MATHEMATICS
NUMERICAL DATA
SPECTRA
URANIUM COMPOUNDS
400702* - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials