Ultra-fast MAS NMR probe

这是一项资金请求，用于购买能够以60千赫或更高频率旋转固体材料样品的双共振核磁共振探针。 该探头将被设计为在11.75 T NMR系统（500 MHz 1H NMR频率）中运行，并将允许阿尔伯塔大学的实验人员以大约两倍于目前可能的频率旋转样品。 固体样品围绕相对于所施加磁场倾斜54.73561度（“魔角”）的轴的超高速旋转将大大扩展研究人员的能力。 首先，涉及顺磁系统的实验将极大地受益于快速样品旋转能力，因为较少的旋转边带将导致较少的杂乱光谱。 此外，在自旋边带中正态分布的信号强度将集中在“各向同性”NMR峰中。 其次，超快NMR探头中使用的小型射频线圈（直径1.3 mm）可以更好地耦合射频脉冲和样品的核磁矩。 这导致更好的1H-去偶效率和“稀自旋”NMR谱的窄化。 最后，对于大量自旋（例如，1H）通过超快速样品旋转实现的分辨率是通过繁琐的多脉冲技术实现的同向偶极去耦的有效替代方案。 由于这种“线变窄”，包括间接1H检测实验在内的许多2D技术变得可行。 最近的固体核磁共振文献表明，许多新的技术和应用涉及超快MAS等待被发现。

This is a request for funds to purchase a double-resonance NMR probe capable of spinning samples of solid materials at frequencies of 60 kHz or greater.  The probe will be designed to operate in an 11.75 T NMR system (500 MHz 1H NMR frequency) and will allow experimentalists at the University of Alberta to spin samples at frequencies approximately double those currently possible.  Ultra-fast spinning of solid samples about an axis inclined at 54.73561 degrees (the "magic-angle") with respect to the applied magnetic field will expand the capabilities of researchers considerably.  First, experiments involving paramagnetic systems will greatly benefit from the rapid sample spinning capabilities because fewer spinning side bands will result in less cluttered spectra.  Furthermore, the signal intensities that are normally distributed in the spinning sidebands will be concentrated in the "isotropic" NMR peak(s).  Second, the small radio-frequency coils used in ultra-fast NMR probes (diameter 1.3 mm) allow for better coupling of the radio-frequency pulses and the nuclear magnetic moments of the sample.  This leads to better 1H-decoupling efficiency and narrowing of "dilute-spin" NMR spectra.  Finally, for abundant spins (e.g., 1H) the resolution achieved via ultra-fast sample spinning is an effective alternative to homonuclear dipolar decoupling via tedious multipulse techniques.  Because of this "line-narrowing", many 2D techniques including indirect 1H-detection experiments become feasible.  The very recent solid-state NMR literature indicates that many new techniques and applications involving ultra-fast MAS are waiting to be discovered.