Temperature Dependence of the ESR Spectrum of CO2−CF2CFCO2− in Irradiated Sodium Perfluorosuccinate
1971; American Institute of Physics; Volume: 54; Issue: 8 Linguagem: Inglês
10.1063/1.1675347
ISSN1520-9032
AutoresLowell D. Kispert, Max T. Rogers,
Tópico(s)Organic and Molecular Conductors Research
ResumoIrradiated single crystals of sodium perfluorosuccinate show ESR spectra at 300°K characteristic of a single CO2−CF2CFCO2− radical, but on cooling below 130°K the spectra show that motion has been frozen out and that the radicals occupy two crystallographically nonequivalent positions. The hyperfine interaction tensors for one α- and two β-fluorine atoms of each radical have been determined at 77°K and compared with those of the 300°K radical. The average of the hyperfine tensors for the two radicals at 77°K is shown to be close to the observed tensor for the single radical at 300°K. Motional averaging by oscillation about the central C–C bond is indicated. Crystals of sodium perfluorosuccinate irradiated and observed at 77°K without warming up show the presence of a single radical with a somewhat different orientation in the crystal lattice than the room temperature radical or either of the radicals obtained on cooling the room temperature radical to 77°K.
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