Fluorescence from γ-irradiated solutions of naphthalene and naphthalene-d8. Effect of an applied magnetic field

Dixon, R.S.; Sargent, F. P.; Lopata, V. J.; Gardy, Edward Michael

doi:10.1016/0009-2614(77)85317-7

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…2 and 3 is consistent with the theory (2, 3), and with our earlier results (6)(7)(8). The enhancement of the emission intensity increases with increasing magnetic field and approaches a plateau at fields > 0.1 T. The high field value varies with solvent in the order cyclohexane < squalane < isooctane for all solutes.…”

Section: Discussionsupporting

confidence: 91%

“…Thus the rate of loss of spin correlation was calculated to be lower for deuterated compounds (2, 3), leading to a smaller magnetic field effect at high fields. This has been confirmed experimentally with naphthalene and naphthalene-d, (8). However, at low fields, the opposite effect was observed, i.e., the enhancement of the fluorescence intensity was higher for naphthalene-d, than for naphthalene.…”

supporting

confidence: 55%

“…For an aromatic hydrocarbon, M, in an alkane solvent, S, the major reactions leading to [8] S* + M + M * + S excited state formation via ion recombination are as The emission observed in our experiments is the follows :…”

Section: Discussionmentioning

confidence: 80%

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Magnetic field effect on the fluorescence from γ-irradiated solutions of perfluorocarbons

Dixon¹,

Lopata²

1979

Can. J. Chem.

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ROBERT SMITH DIXON and VINCENT JOHN LOPATA. Can. J. Chem. 57,3023 (1979). The effect of an applied magnetic field on the fluorescence from y-irradiated solutions of perfluorobiphenyl and perfluoronaphthalene has been measured in various solvents. In all the solvents used (cyclohexane, squalane, isooctane) the fluorescence intensity increases with increasing field and tends towards a plateau at high fields (>0.1 T). At low fields, the fluorescence enhancement is smaller for the perfluorocarbons than for the parent hydrocarbons, due to the larger electron-nuclear hyperfine coupling and broader spread of the hyperfine levels in the radical ions of the perfluorocarbons. At high fields the fluorescence enhancement is also smaller for the perfluorocarbons than for the parent hydrocarbons, indicating a larger relative proportion of prompt (field-independent) fluorescence for the perfluorocarbons than for the parent hydrocarbons.ROBERT SMITH DIXON et VINCENT JOHN LOPATA. Can. J. Chem. 57,3023 (1979) On a mesure dans differents solvants I'effet d9un champ magnktique applique sur la fluoroscence provenant des soIu?ions de perfluorobiphCnyles et perfluoronaphtalenes irradites aux rayons y. Dans tous les solvants utilises (cyclohexane, squalane, isooctane) i'intensite de la fluorescence augmente avec le champ et tend vers un plateau pour des valeurs &levees du champ (> 0.1 T). Lorsque le champ est faible la fluorescence provenant des perfluorocarbures augmente plus faiblement que celle relike aux hydrocarbures apparentes. Ceci est dQ a un pius grand couplage hyperfin electron-noyau et a un etalen~ent plus vaste des niveaux hyperfins des ions radicalaires des perfluorocarbures. A champs forts I'augmentation de la fluorescence est egalement plus petite pour les perfluorocarbures que pour les hydrocarbures apparentis indiquant ainsi une plus grande proportion re!ative de Auorescence rapide (~ndependante du champ) dans le cas des perfluorocarbures que dans les cas des hydrocarbures apparentis.[Traduit par le journal]Large yields of electrons and cations are produced following absorption of ionizing radiation by a liquid. In nonpolar liquids, the major fraction of the ion pairs produced by y or electron irradiation does not separate completely but undergoes geminate recombination. This produces electronically excited singlet and triplet states, the relative yields of which have been predicted to change in an applied magnetic field (1-3). Such an effect has now been observed in both pulse (4-6) and y-irradiated (6-8) solutions of aromatic hydrocarbons in alkane solvents. Recently, experiments using the single photon counting technique have confirmed the effect (9-1 1).When a pair of solute radical ions M' and Mrecombine geminately, loss of spin correlation, i.e., a change from singlet to triplet, occurs because of the isotropic hyperfine interactions between the unpaired electrons and the hydrogen nuclei of M' and M-. A magnetic field was predicted to decrease the rate of loss of spin correlation leading to an increase in singl...

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Section: Discussionsupporting

confidence: 91%

supporting

confidence: 55%

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Magnetic field effect on the fluorescence from γ-irradiated solutions of perfluorocarbons

Dixon¹,

Lopata²

1979

Can. J. Chem.

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“…fluorene, anthracene, naphthalene) in hydrocarbon solvents (e.g. squalane, cyclohexane) that form magnetically sensitive, geminate radical ion pairs upon illumination and which recombine to fluorescent excited states; [18][19][20][21][22][23] and photoexcited pyrene and N,N-dimethylaniline solutions for which spin-selective recombination results in a fluorescent exciplex. 17,24,25 An alternative two-colour approach, in which a second excitation source excites fluorescence in a reaction product, has been used to study the photochemistry of anthraquinone in micellar solutions.…”

Section: Introductionmentioning

confidence: 99%

Sensitive fluorescence-based detection of magnetic field effects in photoreactions of flavins

Evans

Storey

et al. 2015

Phys. Chem. Chem. Phys.

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Magnetic field effect studies have been conducted on a variety of flavin-based radical pair systems chosen to model the magnetosensitivity of the photoinduced radical pairs found in cryptochrome flavoproteins. Cryptochromes are blue-light photoreceptor proteins which are thought to mediate avian magnetoreception, an hypothesis supported by recent in vitro observations of magnetic field-dependent reaction kinetics for a light-induced radical pair in a cryptochrome from the plant Arabidopsis thaliana. Many cryptochromes are difficult to express in large quantities or high concentrations and are easily photodegraded. Magnetic field effects are typically measured by spectroscopic detection of the transient radical (pair) concentrations. Due to its low sensitivity, single-pass transient absorption spectroscopy can be of limited use in such experiments and much recent work has involved development of other methodologies offering improved sensitivity. Here we explore the use of flavin fluorescence as the magnetosensitive probe and demonstrate the exceptional sensitivity of this technique which allows the detection of magnetic field effects in flavin samples at sub-nanomolar concentrations and in cryptochromes.

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Optical detection of ESR absorption of short-lived ion-radical pairs produced in solution by ionizing radiation

Анисимов

Grigoryants

Molchanov

et al. 1979

Chemical Physics Letters

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Fluorescence from γ-irradiated solutions of naphthalene and naphthalene-d8. Effect of an applied magnetic field

Cited by 10 publications

References 11 publications

Magnetic field effect on the fluorescence from γ-irradiated solutions of perfluorocarbons

Magnetic field effect on the fluorescence from γ-irradiated solutions of perfluorocarbons

Sensitive fluorescence-based detection of magnetic field effects in photoreactions of flavins

Optical detection of ESR absorption of short-lived ion-radical pairs produced in solution by ionizing radiation

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