Magnetic Field Effect on Picosecond Electron Transfer

Gilch, Peter; Pöllinger-Dammer, Florian; Musewald, Christian; Michel‐Beyerle, M. E.; Steiner, Ulrich

doi:10.1126/science.281.5379.982

Cited by 75 publications

(55 citation statements)

References 15 publications

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“…Finally, it should be noted that the magnetic field effect on Φ ion has been shown to result to more reliable indirectly measured k CR values than Eq. (1) [64,65]. Fig.…”

Section: Determination Of the Cr Rate Constant Of Ion Pairsmentioning

confidence: 98%

Investigations of bimolecular photoinduced electron transfer reactions in polar solvents using ultrafast spectroscopy

Vauthey

2006

Journal of Photochemistry and Photobiology A: Chemistry

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Several controversial questions in the field of bimolecular photoinduced electron transfer reactions in polar solvents are first briefly reviewed. Results obtained in our group using ultrafast spectroscopy and giving a new insight into these problems will then be described. They concern the driving force dependence of the charge separation distance, the formation of the reaction product in an electronic excited state, the absence of normal region for weakly exergonic charge recombination processes and the excitation wavelength dependence of the CR dynamics of donor-acceptor complexes.

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“…Finally, it should be noted that the magnetic field effect on Φ ion has been shown to result to more reliable indirectly measured k CR values than Eq. (1) [64,65]. Fig.…”

Section: Determination Of the Cr Rate Constant Of Ion Pairsmentioning

confidence: 98%

Investigations of bimolecular photoinduced electron transfer reactions in polar solvents using ultrafast spectroscopy

Vauthey

2006

Journal of Photochemistry and Photobiology A: Chemistry

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“…However, chemical change occurs over such a wide range of characteristic times that a 1 GHz electromagnetic field that might be treated as quasi-static for one type of biochemical event would be rapidly varying for another. For example, catalyzed reactions occur on the nanosecond to picosecond scale (Gilch et al 1998;Pilet et al 2004;Schramm 2005;Clore and Schwieters 2006) but synthesis and folding of macromolecules can take several seconds or even much longer (Martin and Schmid 2003).…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluations of Mechanisms of Radiofrequency Interactions With Biological Molecules and Processes

Sheppard¹,

Swicord²,

Balzano

2008

Health Physics

111

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The complexity of interactions of electromagnetic fields up to 10(12) Hz with the ions, atoms, and molecules of biological systems has given rise to a large number of established and proposed biophysical mechanisms applicable over a wide range of time and distance scales, field amplitudes, frequencies, and waveforms. This review focuses on the physical principles that guide quantitative assessment of mechanisms applicable for exposures at or below the level of endogenous electric fields associated with development, wound healing, and excitation of muscles and the nervous system (generally, 1 to 10(2) V m(-1)), with emphasis on conditions where temperature increases are insignificant (<<1 K). Experiment and theory demonstrate possible demodulation at membrane barriers for frequencies < or =10 MHz, but not at higher frequencies. Although signal levels somewhat below system noise can be detected, signal-to-noise ratios substantially less than 0.1 cannot be overcome by cooperativity, signal averaging, coherent detection, or by nonlinear dynamical systems. Sensory systems and possible effects on biological magnetite suggest paradigms for extreme sensitivity at lower frequencies, but there are no known radiofrequency (RF) analogues. At the molecular level, vibrational modes are so overdamped by water molecules that excitation of molecular modes below the far infrared cannot occur. Two RF mechanisms plausibly may affect biological matter under common exposure conditions. For frequencies below approximately 150 MHz, shifts in the rate of chemical reactions can be mediated by radical pairs and, at all frequencies, dielectric and resistive heating can raise temperature and increase the entropy of the affected biological system.

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“…Recently, the present authors and collaborators reported on sub-picosecond time-resolved experiments with a real-time chemical monitoring of the magnetic Larmor clock 34 . Here a photoexcited dye (oxonine, Ox + ) reacts with the electron donor ethylferrocene (Fc-Et) according to…”

Section: (4k T S )mentioning

confidence: 99%

High Magnetic Fields in Chemistry

Steiner

Gilch²

2003

High Magnetic Fields

Self Cite

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Recent applications of large (∼ 1 T -∼ 30 T) magnetic fields in modern chemical research are reviewed. Magnetic field effects of chemical relevance appear on the levels of quantum mechanics, thermodynamics, and macroscopic forces. Quantum mechanical magnetic field effects are governed by the Zeeman interaction and are borne out as static and dynamic effects in spectroscopy and in chemical kinetics. Magnetic circular dichroism (MCD) spectroscopy and magnetic fluorescence quenching in the gas phase serve to illustrate the former, while radical pair spin chemistry is representative of the latter. The principles of the radical pair mechanism are outlined and highfield applications are illustrated in some detail for photo-induced electron transfer reactions of some transition metal complexes. Thermodynamic effects concern the magnetization of chemical samples, which is the focus of magnetochemistry or -more modern -molecular magnetism, and the equilibrium of chemical reactions. Representative examples of both aspects are described. Finally, the exploitation of orientational forces caused by the magnetic anisotropy of larger particles (from macromolecules to micro-crystals) is exemplified. Crystal growth in a magnetic field may hold a potential for achieving better control of the quality of protein crystals for structural analysis.

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Magnetic Field Effect on Picosecond Electron Transfer

Cited by 75 publications

References 15 publications

Investigations of bimolecular photoinduced electron transfer reactions in polar solvents using ultrafast spectroscopy

Investigations of bimolecular photoinduced electron transfer reactions in polar solvents using ultrafast spectroscopy

Quantitative Evaluations of Mechanisms of Radiofrequency Interactions With Biological Molecules and Processes

High Magnetic Fields in Chemistry

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