Dynamic Nuclear Polarization Solid-state Nuclear Magnetic Resonance Spectroscopy of Insensitive Nuclear Spins.

分子或材料的物理性质是原子紧密排列在一起的直接结果。因此，利用科学方法直接观察这些原子之间的连通性是至关重要的。原子是非常小的物体，大约在10-10米左右，或者相当于从太阳看地球上的一所房子。它们比可见光的波长还小，因此太小而无法被肉眼看到。科学家们依靠使用间接方法来观察这些原子。核磁共振（NMR）光谱学是观察这些原子最强大的技术。核磁共振通常与磁共振成像有关，通常缩写为MRI，是放射学中用于研究人体解剖结构的医学成像技术。核磁共振光谱学的能力依赖于它对原子长度尺度的敏感性，除了医学之外，它还被用于各个科学领域，尤其是在生物学、化学和物理学领域，以确定物质的结构。特别是固态核磁共振波谱，或固态样品的核磁共振波谱，在确定广泛应用的材料结构方面正变得越来越强大，例如电池、药物和导致疾病的蛋白质。然而，总的来说，核磁共振技术，特别是固态核磁共振技术的主要限制是灵敏度，即信号相对于噪声水平的强度，这阻碍了在几秒钟内快速获取核磁共振信号。动态核极化是显著增强核磁共振信号的一种重要方法。该技术允许几百的灵敏度增强因子导致实验时间减少多达五个数量级。例如，一个持续10分钟的核磁共振实验，如果没有动态核极化，则需要1年以上的时间才能获得相同的信噪比。这完全改变了核磁共振可以测定和研究的原子固态结构的类型。动态核极化依赖于低温下高敏感电子自旋向低敏感核自旋的极化转移。能够进行这些实验的动态核极化仪器直到2010年才商业化。在今天的英国没有。因此，本提案旨在资助海外旅行（如法国和美国），以访问一系列具有各种功能的动态核极化硬件，并研究动态核极化增强固态核磁共振波谱的一些基本方面。这项提议特别感兴趣的是，这项工作将专门针对那些难以（或几乎不可能）通过普通固态核磁共振检测到的原子核，无论是由于低自然丰度（例如17O， 43Ca）还是低共振频率（25Mg, 39K, 107Ag, 183W）或两者的组合，因此是动态核极化等戏剧性敏感增强技术的明确和自然应用。这将成为材料科学、催化和纳米技术等广泛科学领域的直接创新来源。它有可能彻底改变确定材料原子尺度结构的方法，从而推动新型高性能材料的发展。

The physical properties of molecules or materials are a direct consequence of the intimate arrangement of the atoms together. Therefore, the availability of scientific methods to directly see the connectivity between these atoms is essential. Atoms are extremely small objects, in the order of 10-10 meter or equivalent to try to see a single house on the Earth from the Sun. They are smaller than the wavelength of visible light and therefore too small to be seen by the naked eye. Scientists rely on the use of indirect methods to observe these atoms. Nuclear Magnetic Resonance (NMR) spectroscopy is the most powerful technique to see these atoms. NMR is commonly related to Magnetic Resonance Imaging, often abbreviated to MRI, and is a medical imaging technique used in radiology to investigate the anatomy of a body. The power of NMR spectroscopy relies on its sensitivity of the atomic length scale, and is used in addition to medicine, across the sciences, and especially in biology, chemistry and physics to determine the structure of matter. In particular, solid-state NMR spectroscopy, or NMR spectroscopy of solid-state samples, is becoming increasingly powerful to determine the structure of materials involved in a very wide range of applications, such as batteries, pharmaceuticals drugs and proteins responsible for diseases. However, the main limitation of the NMR technique in general, and solid-state NMR in particular, is the sensitivity, i.e. the intensity of signals with respect to the noise level, preventing fast acquisition of the NMR signals in seconds. One very important method to dramatically enhance the NMR signals is dynamic nuclear polarization. This technique permits a sensitivity enhancement factor of several hundred leading to reduction in experimental times of up to five orders of magnitude. For example, an NMR experiment lasting 10 min with dynamic nuclear polarization will require more than 1 year without dynamic nuclear polarization to obtain identical signal to noise ratio. This changes completely the type of atomic solid-state structures that could be determined and studied by NMR. Dynamic nuclear polarization relies on a transfer of polarization from the highly sensitive electron spins to the low sensitive nuclear spins at cryogenic temperatures. Dynamic nuclear polarization instruments capable of performing these experiments have only been available commercially since 2010. There are none in the United Kingdom today. Hence, this proposal aims at funding overseas travel to countries (such as France and the United States) to access a range of dynamic nuclear polarization hardware with various capabilities, and investigate some fundamental aspects of dynamic nuclear polarization enhanced solid-state NMR spectroscopy. Of particular interest to this proposal is that the work will exclusively target nuclei that are difficult (or nearly impossible) to detect by normal solid-state NMR, either due to a low natural abundance (e.g. 17O, 43Ca) or a low resonance frequency (25Mg, 39K, 107Ag, 183W) or a combination of both, and is therefore a clear and natural application of a dramatic sensitive enhancement technique such as dynamic nuclear polarization. This will be the source of immediate innovations in a very wide range of areas across science such as in materials science, catalysis and nanotechnology. It has the potential to completely revolutionize approaches to the determination of the atomic scale structure of materials, thereby driving the development of new high performance materials.