Numerical simulation of ESR spectra of nitrixides as a method of investigation. Andrey Kh. Vorobiev Moscow State University. Typical result of simulation of single ESR spectrum: qualitative accordance; small deviations from experiment. SiON(O ) CD 3. Rus.Chem Bull.V.50, No.12, p.2384.
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Rus.Chem Bull.V.50, No.12, p.2384
Typical result of simulation of temperature method of investigation.
dependence of ESR spectrum:simulation of one spectrum is satisfactory;deviations from experiment are more then experimental noise.
Proposed thesis method of investigation.: Quantitativemodelling of spectra
produces more reliable and informative results
Term "Quantitative modelling" means coincidence of experimental and calculated spectra within experimental errors.
Practice shows that for quantitative and reliable
simulation is necessary:
0. Quality of spectra recorded
(subtract base line, avoid overmodulation, saturation, etc.);
1. Simulation of a set spectra (temperature dependence, angular dependence etc).;
2. Variation of parameters using least-squire minimisation method. (It gives impartial verification of your hypothesis).
convolution of isotropic
Gauss and Lorentz lines
convolution of axial
Gauss and Lorentz lines
TEMPON in polystyrene 110K
Admixture of species with other magnetic parameters
gives marked component.
rigid limit spectrum,
spectrum of slow rotation
spectrum of fast rotation
TEMPON absorbed on
Na-mordenite in presence of water vapor
TEMPON in porous teflon AF-2400
Deviations are more
then experimental errors!
High temperature part
Conclusion: quantitative simulation gives additional information even in the case of low-informative spectra
Moves around three axes should be
taken into account in general.
We thank Prof. Kalman Hideg
and Dr.Tamas Kalai
for the gift of this substance.
Example of simulation of set of ESR spectra:Angular dependence of ESR spectrum.
Distribution function is presented in molecular frame
J.Magn.Res. 2005, 175, No.1 pp.146
Dr. Vladimir Gurman determined by quntitative simulation of spectra.
Dr. Tatiana Klimenko
took part on presented work