| 1. |
- Antzutkin, Oleg, et al.
(author)
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Optically dectected ESR (OD-ESR) of iron-radical pairs in colored solutions : observation of transient trans-Azobenzene radical cation
- 1993
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In: Applied Magnetic Resonance. - : Springer- Verlag. - 0937-9347 .- 1613-7507. ; 5:1, s. 77-86
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Journal article (peer-reviewed)abstract
- Trans-azobenzene dissolved in different liquid hydrocarbons absorbs fluorescence arising from all acceptors previously used in Fluorescence Detected Magnetic Resonance (FDMR) and Optically Detected ESR (OD ESR) spectroscopy making optical detection impossible. In this report a new acceptor, rubrene, having sufficient quantum yield of fluorescence in the red band 550-620 nm, has been proven successful. OD ESR spectra of the radical-ion pair trans-azobenzene+/rubrene- were detected in liquid squalane (2,6,10,15,19,23-hexamethyl-tetracosane) solution in the temperature range 294-243 K. The experimental isotropic hyperfine splittings of the radical cation of trans-azobenzene (a(N) = 1.4 mT) have been compared with those from MNDO/INDO calculations and with those of earlier work using freon matrix studies.
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| 2. |
- Koptioug, Andrei, 1956-, et al.
(author)
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Effect of External Magnetic Fields and Resonance Radio frequency Radiation on Radical Reactions
- 1990
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In: Physica. B, Condensed matter. - : Esevier. - 0921-4526 .- 1873-2135. ; 164:1-2, s. 200-204
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Journal article (peer-reviewed)abstract
- It is well known that an external magnetic field can affect the rate of singlet-triplet transitions in a radical pair and hence its recombination probability in liquid. Resonance radiofrequency (RF) radiation induces quantum beats in the kinetics of radical pair recombination. At high RF field amplitudes the singlet-triplet transitions in radical pairs can be efficiently suppressed.
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| 3. |
- Morozov, V. A., et al.
(author)
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Multiquantum resonances in low-field optically detected ESR of radical-ion pairs
- 1991
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In: Molecular Physics. - : Taylor & Francis. - 0026-8976 .- 1362-3028. ; 73:3, s. 517-540
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Journal article (peer-reviewed)abstract
- Multiquantum resonances in low-field optically-detected electron spin resonance (ESR) spectra of radiation-induced radical-ion pairs of aromatic acceptors in liquid and some polymeric solutions have been studied experimentally and theoretically. Corresponding resonances occur in spectra under the action of relatively intense radiofrequency (RF) pumping, when usual signals are inverse due to spin-locking effect. Special experiments have been carried out to prove that such resonances are not caused by the apparatus. The dependencies of resonance shifts and intensities on the radiofrequency field amplitude for various polarizations of the RF field have been studied. The case of pumping with two independent RF generators has also been analysed. A general theory for multiquarium optically detected ESR spectra of radicalion pairs in liquid solutions has been developed, with spin relaxation processes being neglected. The theory has been applied to calculating multiquantum resonance parameters in transverse RF fields (H1 ⊥ H0) of various polarizations. The mechanism of multiquantum resonance spin dynamics of radical pairs (RP) has been analysed in detail. The shapes of OD ESR spectra components have been studied for the Poisson distribution of RP lifetimes. The developed theory shows qualitative agreement with experimental results
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