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Title:Magnetic Resonance Studies of Inorganic Oxides and a New Pulse Programming System for Pulsed EMR
Author(s):Schwartz, Dwight Allen
Doctoral Committee Chair(s):Belford, R. Linn
Department / Program:Chemical Physics
Discipline:Chemical Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Materials Science
Abstract:We have investigated several inorganic oxide systems using nuclear and electron magnetic resonance spectroscopies and also report a new pulse programming system for a pulsed S-band EMR spectrometer. We show in a study of simple perovskites (Ca,Sr,Ba)(Ti,Zr) O$\sb3$ that magic-angle spinning O-17 NMR provides unique, highly-resolved spectra in these materials and gives evidence of being useful as a diagnostic tool in mixed phase materials (A$\sb{x}A\sbsp{1-x}{\prime})$BO$\sb3.$ Various used NMR and EMR techniques to study of the commercial borosilicate glasses CGW-3320, CGW-7502, CGW-7740 (Pyrex) and GSC-4, and T-08 (pure silica glass) which had received 5-10 gigarad doses of Co-60 gamma-radiation in the presence and absence of hydrogen gas. We show that B-11, Al-27 and Si-29 MAS NMR spectra contain indications of structural changes in these glasses as a result of large doses of radiation. We also observed the reduction of trace Ti(IV) to Ti(III) when H$\sb2$ gas was present during irradiation of glass samples. Static NMR and EMR studies in the (Na,Li)PO$\sb3$ system indicate a possible mixed alkali effect in the spin-lattice relaxation of Na-23 in NaPO$\sb3$ and Li$\rm\sb{0.4}Na\sb{0.6}PO\sb3.$ Static Na-23 NMR studies of NaPO$\sb3$ reveal the presence of different structural or dynamical environments as a function of temperatures between 23-566 C. We have investigated glass and glass fibers of Li$\rm\sb{0.6}Na\sb{0.4}PO\sb3$ and Na(P$\rm\sb{0.99},V\sb{0.01})O\sb3,$ and show P-31 NMR and EMR evidence that these materials remained structurally isotropic when pulled into fibers. We show that vanadium (in Na(P$\rm\sb{0.99},V\sb{0.01})O\sb3)$ appears to suppress radiolytic unpaired electron and hole defect production which does take place in nominally vanadium-free NaPO$\sb3$ during small doses of gamma-radiation. We describe hardware and software developed for a pulse programming system for a pulsed S-band EMR spectrometer. This system supports user-programmable automatic independent control of all pulse sequence parameters (pulse and delay durations, and pulse phases). We demonstrate the capabilities of this new system in 2-, 3-, and 4-pulse EMR experiments, and also demonstrate a new software suite for interactive simulation and simulation optimization of electron spin echo envelope modulation (ESEEM) patterns using a genetic algorithm.
Issue Date:1997
Description:561 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.
Other Identifier(s):(MiAaPQ)AAI9737245
Date Available in IDEALS:2015-09-25
Date Deposited:1997

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