Abstract
EPR (electron paramagnetic resonance) is a form of spectroscopy in which the measuring beam has a wavelength of 3 cm., and thus has no effect on living matter. Photosynthetic organisms, or their chloroplasts or chromatophores, become paramagnetic when illuminated with visible light. What this means is diagrammed in Figure 1; paramagnetism is due to unpaired electrons. It is one of the first detectable events after the absorption of a photon. If enough electrons are unpaired (or there are enough free radicals of a given species), one sees an absorption
A schematic representation of the transition between the diamagnetic state of material and the paramagnetic state. The arrows represent electrons.
peak at a given ration of magnetic field and microwave frequency which is expressed as a so=-called g-value and is analogous to wavelength in light spectroscopy.
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© 1972 Dr. W. Junk N.V. Publishers, The Hague
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Weaver, E.C. (1972). Intermediate Electron Transport in Porphyridium: EPR Studies. In: Forti, G., Avron, M., Melandri, A. (eds) Photosynthesis, two centuries after its discovery by Joseph Priestley. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-2935-3_31
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DOI: https://doi.org/10.1007/978-94-010-2935-3_31
Publisher Name: Springer, Dordrecht
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