Systematics of valence variation in cerium determined by L/sub III/ absorption
L/sub III/ absorption spectra on approximately 100 Ce intermetallic and insulating compounds with elements from all major groups of the periodic table have been measured. A simple fitting procedure based upon a single particle picture is used to estimate the white line widths and intensities of these spectra. The validity of the single particle picture is examined. A quantitative estimate for the Ce 5d bandwidth based upon the linewidth is made. A quantitative estimate of the Ce valence is made based upon the relative intensities of the white lines. The variation in Ce valence is found to be systematic following very general trends. These trends can be explained in terms of the cohesive energy and, more specifically, by the position of the Fermi energy with respect to the vacuum. Simple arguments are given to explain the Ce valence variation in compounds containing 3d, 4d, and 5d transition elements. These arguments incorporate the transition element d-electron correlation energy of having two electrons in one d orbital, and the d-bandwidth. The line widths also show systematic variation. The line widths for nonmetallic compounds are very narrow and slightly shifted to higher transition energy than the metallic compounds. The line widths for integral valent isostructural intermetallics are inversely correlated with the lattice cell volume. Gross trends in the linewidth are used to infer variations in the f state hybridization of Ce.
- Research Organization:
- Rutgers--the State Univ., New Brunswick, NJ (USA)
- OSTI ID:
- 5285136
- Country of Publication:
- United States
- Language:
- English
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