Bibliographic Citation
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Title | Peroxy spin probes as motional probes in polymers and on oxide surfaces |
Creator/Author | Kevan, L. ; Schlick, S. |
Publication Date | 1986 May 08 |
OSTI Identifier | OSTI ID: 5817593 |
Other Number(s) | CODEN: JPCHA |
Resource Type | Journal Article |
Resource Relation | J. Phys. Chem. ; Vol/Issue: 90:10 |
Research Org | Univ. of Houston, TX |
Subject | 400201 -- Chemical & Physicochemical Properties ;400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987); OXIDES-- DYNAMICS;PEROXY RADICALS-- ELECTRON SPIN RESONANCE;POLYMERS-- DYNAMICS;SURFACES-- DYNAMICS; BLOCH EQUATIONS;EXPERIMENTAL DATA;GYROMAGNETIC RATIO;HYPERFINE STRUCTURE;MAGNETIC RESONANCE;TENSORS |
Related Subject | CHALCOGENIDES;DATA;EQUATIONS;INFORMATION;MAGNETIC RESONANCE;MECHANICS;NUMERICAL DATA;OXYGEN COMPOUNDS;RADICALS;RESONANCE |
Description/Abstract | Electron spin resonance spectra of peroxy radicals, ROO, at low temperatures indicate a rhombic g tensor with g/sub 1/ approx.^2.04, g/sub 2/ approx.^2.008, and g/sub 3/ approx.^2.002.^Spectra change reversibly with temperature and express the g-tensor averaging due to motion.^In the low- and high-temperature limits, spectra are easy to interpret by inspection.^In the intermediate temperature range, however, extra lines appear and the complex spectra can usually only be interpreted by simulation, using a motional model.^Satisfactory calculated spectra can be obtained by the modified Bloch equations for magnetic relaxation with the addition of a kinetic term reflecting the motional model.^Comparison of calculated spectra as a function of the lifetime of the radical in a specific orientation with experimental results as a function of temperature allows determination of the activation energy for the motion.^This approach has been applied to a variety of polymeric systems and to peroxy-type radicals on surfaces.^Chain axis rotation with large jump angles in polymers, C-O bond rotations, as well as helical motions of the polymer chain ends have been identified and characterized.^41 references, 19 figures, 1 table. |
Country of Publication | United States |
Language | English |
Format | Pages: 1998-2007 |
System Entry Date | 2001 May 13 |
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