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Chiral-induced spin selectivity in the formation and recombination of radical pairs: cryptochrome magnetoreception and EPR detection
- Source :
- New Journal of Physics
- Publication Year :
- 2021
- Publisher :
- IOP Publishing, 2021.
-
Abstract
- That the rates and yields of reactions of organic radicals can be spin dependent is well known in the context of the radical pair mechanism (RPM). Less well known, but still well established, is the chiral-induced spin selectivity (CISS) effect in which chiral molecules act as spin filters that preferentially transmit electrons with spins polarized parallel or antiparallel to their direction of motion. Starting from the assumption that CISS can arise in electron transfer reactions of radical pairs, we propose a simple way to include CISS in conventional models of radical pair spin dynamics. We show that CISS can (a) increase the sensitivity of radical pairs to the direction of a weak external magnetic field, (b) change the dependence of the magnetic field effect on the reaction rate constants, and (c) destroy the field-inversion symmetry characteristic of the RPM. We argue that CISS polarization effects could be observable by EPR (electron paramagnetic resonance) of oriented samples either as differences in continuous wave, time-resolved spectra recorded with the spectrometer field parallel or perpendicular to the CISS quantization axis or as signals in the in-phase channel of an out-of-phase ESEEM (electron spin echo envelope modulation) experiment. Finally we assess whether CISS might be relevant to the hypothesis that the magnetic compass of migratory songbirds relies on photochemically-formed radical pairs in cryptochrome flavoproteins. Although CISS effects offer the possibility of evolving a more sensitive or precise compass, the associated lack of field-inversion symmetry has not hitherto been observed in behavioural experiments. In addition, it may no longer be safe to assume that the observation of a polar magnetic compass response in an animal can be used as evidence against a radical pair sensory mechanism.
- Subjects :
- Physics
Spin polarization
General Physics and Astronomy
Magnetoreception
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Photochemistry
01 natural sciences
0104 chemical sciences
law.invention
Cryptochrome
law
0210 nano-technology
Selectivity
Spin (physics)
Electron paramagnetic resonance
Recombination
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- New Journal of Physics
- Accession number :
- edsair.doi.dedup.....429c51d4df63e5e1477c33b94056e22e