Unified Theory of the Exciplex Formation/Dissipation

Khokhlova, Svetlana S.; Burshteǐn, A. I.

doi:10.1021/jp1047216

Cited by 4 publications

(12 citation statements)

References 16 publications

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“…MFE in the emission band of exciplexes upon optical generation is well-known 28 and is based on the reversibility of transitions between the radical ion pair state and the exciplex in the solvent of the corresponding viscosity and polarity. [29][30][31][32][33][34][35][36][37] For systems lending themselves to exciplex formation, under ionizing irradiation MFE has so far only been observed in polar solvents, e.g. for the system pyrene/N,N-diethylaniline in methanol.…”

Section: Introductionmentioning

confidence: 99%

Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes

Melnikov

Kalneus

Korolev

et al. 2014

Photochem Photobiol Sci

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X-irradiation of alkane solutions of N,N-dimethylaniline with various organic luminophores produces characteristic emission bands ascribed to the corresponding exciplexes. In contrast to optical generation, which requires diffusion-controlled quenching of excited states, an additional channel of exciplex formation via irreversible recombination of radical ion pairs is operative here, which produces exciplexes in solution with high efficiency even for p-terphenyl and diphenylacetylene having fluorescence decay times of 0.95 ns and 8 ps, respectively. The exciplex emission band is sensitive to an external magnetic field and exerts a very large observed magnetic field effect of up to 20%, the maximum possible value under the conditions of the described experiment.

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Section: Introductionmentioning

confidence: 99%

Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes

Melnikov

Kalneus

Korolev

et al. 2014

Photochem Photobiol Sci

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“…Quantum yields of competing reactions of contact exciplex formation and fluorescence in the absence (a) and presence (b) of excitation quenching by distant ionization. The present theory is represented by solid lines, and the dashed lines were obtained with UT . The rest of the parameters are σ = 6 Å, L = 1.5 Å, c = 0.1 M, k a = 500 Å 3 /ns, k d = 0.03 ns – 1 , W 0 = 10 ns –1 , k f ≈ 4347 Å 3 /ns, τ E = 15 ns, and τ D = 10 ns.…”

Section: Irreversible Photo-ionization Versus Exciplex Formationmentioning

confidence: 99%

“…The former (IET) is employed here whereas the latter (DET) is the base of our UT used for comparison. 16 …”

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

“…The natural contact reaction of exciplex formation cannot be included in such a consideration because it is reversible in principle (see chapter VD in ref ). To make it possible, the unified theory (UT) was heuristically extended and employed to confirm the existence of the screening effect in the reaction of distant (though irreversible) electron transfer competing with contact (reversible) exciplex formation …”

Section: Introductionmentioning

confidence: 99%

“…The present theory is represented by solid lines, and the dashed lines were obtained with UT 16. The rest of the parameters are σ = 6 Å, L = 1.5 Å, c = 0.1 M, k a = 500 Å 3 /ns, k d = 0.03 ns À1 , W 0 = 10 ns À1 , k f ≈ 4347 Å 3 /ns, τ E = 15 ns, and τ D = 10 ns.…”

mentioning

confidence: 99%

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Screening of Exciplex Formation by Distant Electron Transfer

2011

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The excitation quenching by reversible exciplex formation, combined with irreversible but distant electron transfer, is considered by means of the integral encounter theory (IET). Assuming that the quenchers are in great excess, the set of IET equations for the excitations, free ions, and exciplexes is derived. Solving these equations gives the Laplace images of all these populations, and these are used to specify the quantum yields of the corresponding reaction products. It appears that diffusion facilitates the exciplex production and the electron transfer. On the other hand the stronger the electron transfer is, the weaker is the exciplex production. At slow diffusion the distant quenching of excitations by ionization prevents their reaching the contact where they can turn into exciplexes. This is a screening effect that is most pronounced when the ionization rate is large.

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Exciplex Formation Accompanied with Excitation Quenching

Fedorenko

Burshteǐn

2010

J. Phys. Chem. A

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The competence of the reversible exciplex formation and parallel quenching of excitation (by electron or energy transfer) was considered using a non-Markovian pi-forms approach, identical to integral encounter theory (IET). General equations accounting for the reversible quenching and exciplex formation are derived in the contact approximation. Their general solution was obtained and adopted to the most common case when the ground state particles are in great excess. Particular cases of only photoionization or just exciplex formation separately studied earlier by means of IET are reproduced. In the case of the irreversible excitation quenching, the theory allows specifying the yields of the fluorescence and exciplex luminescence, as well as the long time kinetics of excitation and exciplex decays, in the absence of quenching. The theory distinguishes between the alternative regimes of (a) fast equilibration between excitations and exciplexes followed by their decay with a common average rate and (b) the fastest and deep excitation decay followed by the weaker and slower delayed fluorescence, backed by exciplex dissociation.

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Unified Theory of the Exciplex Formation/Dissipation

Cited by 4 publications

References 16 publications

Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes

Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes

Screening of Exciplex Formation by Distant Electron Transfer

Exciplex Formation Accompanied with Excitation Quenching

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