Diffusion-controlled intermolecular electron transfer studied by transient absorption and degenerate four-wave mixing measurements

Assel, M.; Hofer, Thomas S.; Laubereau, A.; Kaiser, W.

doi:10.1016/0009-2614(95)00027-2

Cited by 3 publications

(7 citation statements)

References 9 publications

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“…In order to show that intermolecular charge hopping from the ion pair is thermodynamically possible, we can follow the framework of Suga and Aoyagui, who utilized the collision frequency and Marcus theory to analyze intermolecular electron transfer rates for a reaction scheme of R 1 - + R 2 → R 1 + R 2 - . ,− This is directly comparable to the second step of the bulk charge separation process in our liquid crystal, but can be followed for the first step also. The rate of intermolecular charge transfer is given by: where Here, Z is the bimolecular collision rate of the uncharged species, Δ G CS is the free energy for charge separation, λ T is the total reorganization energy of the solvent (λ S ) and of the intramolecular bonds (λ i ), r 1 and r 2 are the radii of the reactants, and r 12 is the center-to-center distance between the two reactants.…”

Section: Discussionmentioning

confidence: 99%

Photorefractivity in Nematic Liquid Crystals Containing Electron Donor−Acceptor Molecules That Undergo Intramolecular Charge Separation

et al. 1997

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We report photorefractivity in nematic liquid crystals doped with electron donor−acceptor molecules that undergo intramolecular photoinduced charge separation. We show that subsequent intermolecular electron transfer from the intramolecular ion pairs to neutral donor−acceptor molecules is responsible for the charge migration over macroscopic distances that is required to produce photorefractivity. The results are compared to nematic liquid crystals doped with identical unlinked donors and acceptors that can achieve charge separation only through intermolecular electron transfer. We find that the liquid crystals doped with molecules that first undergo intramolecular charge separation exhibit superior photorefractivity when compared to the same liquid crystals doped with unlinked donors and acceptors. The differing mechanisms for charge generation and charge transport in these liquid crystal composites are analyzed.

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Section: Discussionmentioning

confidence: 99%

Photorefractivity in Nematic Liquid Crystals Containing Electron Donor−Acceptor Molecules That Undergo Intramolecular Charge Separation

et al. 1997

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“…(b) Degenerate four-wave mixing (DFWM) in the self-diffraction geometry is applied as a probing process in the experimental configurations described previously. ,, In short, two input pulses of equal intensity I 1 (vertically polarized) are temporally and spatially overlapped in the sample cuvette, 500 μm in length. The interaction of the two coherent laser beams with the nonlinear medium over a width of approximately 150 μm results in a transient polarization grating …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Now the dynamics of the photoreaction is different from that which is observed after excitation of the DAC. The following reaction scheme may be assumed for the excitation of the donor molecule 5 (for comparison we point to a similar system like perylene/phthalic anhydride , ). After exciting the ground state pyrene via the S 0 → S 1 transition an electron is transferred by encounter between the excited pyrene and the ground state PMDA.…”

Section: Introductionmentioning

confidence: 99%

“…To investigate these quantities, two different techniques are applied: (a) the common pump−probe measurement is used to determine the transient absorption in a certain wavelength range together with related time constants; (b) degenerate four-wave mixing (DFWM) serves as a probing method in combination with optical pumping of the sample. ,, The transient changes of the nonlinear susceptibility χ (3) are studied, yielding the time constants and the molecular hyperpolarizabilities of the molecular states populated in the course of our measurement.…”

Section: Introductionmentioning

confidence: 99%

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Electron Transfer Complexes of the System Pyrene/PMDA Studied by Transient Absorption and Degenerate Four-Wave Mixing Measurements

Assel¹,

Hofer²,

Laubereau³

et al. 1996

J. Phys. Chem.

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The kinetics of the intermolecular electron transfer between pyrene and pyromelitic dianhydride is studied by two experimental techniques: transient absorption measurements and degenerate four-wave mixing after optical excitation by picosecond light pulses. The observed time evolution of the electron transfer reaction depends strongly on the wavelength of the pump pulse. Excitation of pyrene leads to a diffusion-controlled electron transfer (in agreement with theoretical calculations), while excitation of the ground state donor-acceptor complex shows a different time behavior. Comparison of the decay times and the molecular hyperpolarizabilities provides clear evidence for two different excited charge transfer complexes.

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Photoinduced Self-Organization in “Semiconductor World”: Part I. from Protophotosynthesis to Protomembranes

Gradov,

Gradova

2023

Preprint

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This work is the first part of a series of papers on a comprehensive analysis of the processes of prebiotic self-organization and protophotosynthesis on the surface of semiconductor minerals and in systems of natural dispersed semiconductors. Comprehensive analysis within the framework of the "semiconductor world" concept allows integrating a variety of models on a single physical basis - from ZnS world and FeS world (based on inorganic semiconductors) to the PAH world and aromatic world (including organic semiconductors). Thus, we do not put forward a new alternative hypothesis of chemical evolution - a new "chemical world", but only integrate the evolutionary and geochemical criteria of different "chemical worlds" into a single "physical world", which gives one the opportunity to reconstruct and predict the directions of chemical evolution according to the uniform principles of physical chemistry. In the first part of this series we consider photoinduced self-organization and "photo-controlled" evolution of the early protobiological systems performing solar energy conversion on the surface of dispersed semiconductor minerals capable of (photo)catalyzing and photosensitizing prebiological processes. The latter include a transition from the elementary cycles of photocatalytic reactions on the surface of semiconductors to protophotometabolic cycles and protophotosynthesis, from photophysical processes on the surface of mineral semiconductors to photoinduced membrane potentials, from photocontrolled sorption on the surface of such minerals to the formation of photosensitive protomembranes and selection of photosynthetic structures. The evolutionary approach to the analysis of protobiological mechanisms and protobioenergetics within the framework of the "semiconductor world" concept provides a new approach to the study of the last common point of divergence of protobiological systems, where the emergence principles of different energy supply schemes (like the energy source-specific photoautotrophy and substrate-specific chemoautotrophy) merge at the physicochemical level. The proposed integrating scheme is consistent with most biological, geological, and physicochemical concepts, which ensures its complete cross-checking and internal consistency.

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Diffusion-controlled intermolecular electron transfer studied by transient absorption and degenerate four-wave mixing measurements

Cited by 3 publications

References 9 publications

Photorefractivity in Nematic Liquid Crystals Containing Electron Donor−Acceptor Molecules That Undergo Intramolecular Charge Separation

Photorefractivity in Nematic Liquid Crystals Containing Electron Donor−Acceptor Molecules That Undergo Intramolecular Charge Separation

Electron Transfer Complexes of the System Pyrene/PMDA Studied by Transient Absorption and Degenerate Four-Wave Mixing Measurements

Photoinduced Self-Organization in “Semiconductor World”: Part I. from Protophotosynthesis to Protomembranes

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