Intrinsic cathodoluminescence emission from willemite single crystals
| Autor: | E. W. White, R.J.R.S.B. Bhalla |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
Materials science
business.industry Biophysics Willemite Cathodoluminescence Molecular orbital theory General Chemistry engineering.material Condensed Matter Physics Polarization (waves) Biochemistry Molecular physics Atomic and Molecular Physics and Optics Optics engineering Degree of polarization Molecular orbital business Anisotropy Luminescence |
| Zdroj: | Journal of Luminescence. 4:194-200 |
| ISSN: | 0022-2313 |
| DOI: | 10.1016/0022-2313(71)90072-x |
| Popis: | Intrinsic cathodoluminescence emission from oriented willemite (Zn2SiO4) single crystals was studied using a modified electron microprobe. Natural willemite crystals, free of manganese and iron impurities, were used. The emission was found to be strongly polarized for the crystals oriented such that the c-axis was in the surface of the polished section. The electric vector of emission was along the c-axis and the degree of polarization was 0.75. Crystals with orientation such that the c-axis was perpendicular to the surface of the section and along the axis of the light microscope did not show any polarization. This intrinsic emission could not be explained by considering transitions within the Si4+ ion, thus the entire (SiO4)4- tetrahedral complex had to be considered. Molecular orbital theory and symmetry arguments were used to explain anisotropy of emission from (SiO4)4- complex. These arguments led to the conclusion that the symmetry of the (SiO4)4- tetrahedra is reduced to Cs in willemite. Selection rules, for various possible lower symmetries of (SiO4)4- type of molecular orbital complexes, were also calculated as an aid for interpretation of polarized luminescence from such molecules in solids. |
| Databáze: | OpenAIRE |
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