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

固态光- cidnp效应是1994年由Zysmilich和McDermott发现的，已被证明发生在几种电子转移蛋白中，如光合反应中心（rc），并允许核磁共振信号的极大增强。这种效应的发生和强度在很大程度上取决于磁场强度。到目前为止，这一效应只在核磁共振磁体内部可用的高场下进行了研究。在这里，我们想开发和应用一个MAS-NMR穿梭系统，以允许磁体外的感应效应和磁体中心的核磁共振测量。因此，所提出的穿梭系统将结合低场的优势，即高核自旋极化和高场的优势，即高化学位移色散。这样的系统将允许对电子结构的详细研究，发现更多的系统显示的影响，它将允许探索目前的理论的有效性。理论还预测了在弱磁场条件下，包括地球磁场条件下，该效应也会发生。利用一个先进的穿梭系统，利用弱反场，这一理论预测将得到验证。我们特别感兴趣的是地球磁场对光合反应中心蛋白和蓝光光感受器的影响。该效应在地球磁场反应中心的出现，表明核自旋超极化与有效电子转移的功能相关。对蓝光光感受器的成功实验将加强动物导航中依赖光的磁接受依赖于磁场依赖的化学反应的提议。因此，理想情况下，我们的实验将为光合作用中的生物自旋电子自旋阀和控制动物导航的电子-电子-核自旋动力学提供一些实验证据。

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.