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Investigation of structure of Fe 3+ magnetic center in polyparaphenylene
Author(s) -
Vasyukov V. N.,
Shapovalov V. A.,
Dyakonov V. P.,
Dmitruk A. F.,
Aksimentjeva E. I.,
Szymczak H.,
Piechota S.
Publication year - 2002
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10200
Subject(s) - electron paramagnetic resonance , ion , impurity , line (geometry) , atmospheric temperature range , chemistry , atomic physics , range (aeronautics) , spectral line , quantum number , analytical chemistry (journal) , materials science , nuclear magnetic resonance , physics , thermodynamics , geometry , mathematics , organic chemistry , astronomy , chromatography , composite material
In the temperature range between 4.2 and 300 K, the EPR spectrum of the impurity Fe 3+ ion in the organic polyparaphenylene has been investigated. An effect developed as an unusual temperature change of Fe 3+ EPR spectrum has been revealed. The EPR spectrum of powder sample consists of two resonance lines. Line 1 with the effective g ‐value equal to g 1 = 4.21 ± 0.05 is of the maximum intensity at T = 4.2 K. With temperature increase, the intensity of line 1 decreases until vanishing. Line 2 is observed over the whole temperature range. For T = 300 K, the g ‐value of line 2 is g 2 = 2.00 ± 0.09. To study the structure of magnetic ion molecular environment and define nonequivalent positions of the magnetic ion in polyparaphenylene, a calculation was done of the energy of Fe 3+ magnetic ion for various possible molecular environments. It is shown that in polyparaphenylene for the Fe 3+ magnetic ion there are two different stationary molecular environments. The obtained model of magnetic ion molecular environment was used to explain the temperature dependence of the EPR spectrum. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002