Infrared Spectroscopy of Ionic Solids.
Final rept. Jan 69-Jun 71,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
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The research was an investigation of the vibrational spectra of certain classes of crystal structure important to materials science and technology. Specifically, the research was concerned with the characterization of chemical bonding and crystal structure and with the characterization of cation ordering. The relation of the spectra to structure and bonding was studied in suites of compounds with the garnet, C-type rare earth, zircon, fergusonite, scheelite, and monazite structures. It was shown that splittings of certain vibrational bands can be correlated with structural distortion and the factor group splitting with the anisodesmicity ionic versus covalent character of the chemical bonds. The relation of spectra to order-disorder was studied in compounds with various orderings on the spinel structure, on ordered rock salt structures, on ordered corundum structures, and on superstructures based on rock salt and perovskite layers. It was shown that the vibrational spectrum is a very sensitive tool for the detection of ordering. Specific models for ordering can be proven for small unit cells. Author
- Atomic and Molecular Physics and Spectroscopy