Occurrence of the solid-state photo-CIDNP effect at earths magnetic field

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The solid-state photo-CIDNP effect, discovered in 1994 by Zysmilich and McDermott, has been shown to occur in several electron-transfer proteins such as photosynthetic reaction centers (RCs) and allows for enormous enhancement of NMR signals. Occurrence and strength of the effect strongly depend on the magnetic field strength. Up to now, the effect has been studied exclusively at the high fields available inside NMR magnets. Here we want to develop and apply a MAS-NMR shuttle system to allow for induction of the effect outside the magnet and NMR measurement in the center of the magnet. Hence, the proposed shuttle system will combine the advantage of low fields, i.e., high nuclear spin-polarization, with the advantage of high field, i.e. high chemical shift dispersion. Such system will allow for detailed studies on electronic structures, discovering more systems showing the effect and it will allow to explore the validity of the present theory.Theory also predicted the occurrence of the effect at weak magnetic fields including earths magnetic field conditions. With an advanced shuttle system, using a weak counter field, this theoretical prediction will be tested. In particular, we are interested in earths magnetic field effects on photosynthetic reaction center proteins and blue-light photoreceptors. Occurrence of the effect in reaction centers at earths field would suggest a functional relevance of nuclear spin-hyperpolarization of the efficient electron transfer. A successful experiment on blue-light photoreceptors would strengthen the proposal that light-dependent magnetoreception in animal navigation relies on magnetic-field dependent chemical reactivity. Hence, ideally our experiments will provide some experimental evidence on a bio-spintronic spin-valve in photosynthesis and on electron-electron-nuclear spin-dynamics controlling animal navigation.