Spin-mapping of coal structures with ESE and ENDOR
The overall goal of this project is the development of nondestructive techniques for studying the molecular structure of coal by probing the chemical environment of naturally occurring unpaired electrons with a variety of electron magnetic resonance spectroscopies. One exceptionally promising method for investigating molecular structure in complex solids possessing unpaired electrons is Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy. Currently the aim of our S-band ESEEM work is to develop better methods for the interpretation of multifrequency ESEEM data. This problem is extremely difficult, especially for modulation resulting from quadrupolar nuclei (l > 1/2) such as {sup 33}S, {sup 14}N, and {sup 23}Na. We are pursuing two closely related paths toward this goal. One part of this effort is the development of classification system which would make ESEEM spectra more amenable to a preliminary interpretation by visual inspection. This report describes the testing of some of the capabilities of our recently constructed ESE spectrometer by carrying out a detailed investigation of the molecule DPPH, diphenylpicrylhydrazyl, a well-known stable free radical frequently used to test and tune up electron paramagnetic resonance spectrometers, but details of the nitrogen substituents on one of its aromatic rings have been uncertain and, in fact, the focus of a bit of controversy. It therefore made an excellent subject to select for this test. 14 refs., 2 figs.
- Research Organization:
- Illinois Univ., Urbana, IL (USA)
- Sponsoring Organization:
- DOE/FE
- DOE Contract Number:
- FG22-88PC88921
- OSTI ID:
- 6409349
- Report Number(s):
- DOE/PC/88921-7; ON: DE91004334
- Country of Publication:
- United States
- Language:
- English
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Spin-mapping of coal structures with ESE and ENDOR. Thirteenth quarterly report
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Related Subjects
010600* -- Coal
Lignite
& Peat-- Properties & Composition
656002 -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METAL ISOTOPES
AROMATICS
CARBONACEOUS MATERIALS
COAL
COMPUTERIZED SIMULATION
DOCUMENT TYPES
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
ENDOR
ENERGY SOURCES
EVEN-ODD NUCLEI
FOSSIL FUELS
FOURIER TRANSFORMATION
FUELS
INTEGRAL TRANSFORMATIONS
ISOTOPES
LIGHT NUCLEI
MACERALS
MAGNETIC RESONANCE
MATERIALS
MEASURING INSTRUMENTS
MOLECULAR STRUCTURE
NITROGEN 14
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PROGRESS REPORT
RADICALS
RESONANCE
SIMULATION
SODIUM 23
SODIUM ISOTOPES
SPECTRA
SPECTROMETERS
SPECTROSCOPY
STABLE ISOTOPES
SULFUR 33
SULFUR ISOTOPES
TESTING
TRANSFORMATIONS
VITRINITE