Crystals of 34% exchanged Eu$ sp{3+} beta sp{ prime prime}$-alumina were studied using site-selective spectroscopic techniques. The Eu$ sp{3+}$ ions were found to exhibit spectra which could be categorized into three types of emitting centres. These emitting centres are related to the crystallographic sites available for Eu$ sp{3+}$ in $ beta sp{ prime prime}$-alumina, namely the mid-Oxygen and Beevers-Ross sites. The fluorescent lifetimes were measured and were found to be consistent with the site assignments, particularly in the variations possible in the Eu$ sp{3+}$ coordination in mid-Oxygen sites. Analysis of the emission intensities reveals that the calculated site populations are in agreement with previously published X-ray results. Crystal-field analysis of the spectra indicates that the different types of centres are subject to different crystal-field strengths and that effects such as J-mixing play an important role in the observed spectra. Point-charge lattice sum calculations on an idealized structure of the $ beta sp{ prime prime}$-alumina crystal are in qualitative agreement with the crystal-field analysis and also provide a model for the observed inhomogeneous linewidths based on the number of residual sodium atoms in the unit cell. In addition, several anomalous features of the Eu$ sp{3+}$ spectra are described and discussed in terms of the structure of the crystal and its influence on the Eu$ sp{3+}$ ion's energy levels.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.70176 |
| Date | January 1990 |
| Creators | Brown, Andrew P. (Andrew Peter) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001226788, proquestno: AAINN67577, Theses scanned by UMI/ProQuest. |
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