From proton to deuteron relaxometry: The next generation of field-cycling NMR relaxometers

核磁共振弛豫技术通过场循环（FC）技术的应用，在研究各种软物质自旋-晶格弛豫的频率依赖性方面向前迈进了一大步。频率依赖性直接反映了分子动力学。大多数FC研究集中在质子上。由于相关相互作用的多粒子特性，探索了分子重定向和平移的叠加，这通常阻碍了定量的见解。相比之下，氘FC NMR仅检测重取向，因此，理论理解和计算机模拟非常方便。人们还受益于NMR的同位素选择性，与其他方法相比，NMR允许以更具体的方式解释数据。然而，由于氘核磁共振频率很小，目前的FC弛豫仪不适合常规的FC核磁共振研究。相反，必须开发新一代的弛豫计。在复杂设计的线圈系统中快速切换数千安培，并达到高精度的强磁场，这使得任务非常苛刻。这是本项目的目标，以实现这一目标，并使氘FC NMR的常规技术的“分子流变学”。同样，对其他核如7 Li、13 C和31 P的研究也将成为可能，甚至质子弛豫测量也将从中受益。

By applying the field-cycling (FC) technique, NMR relaxometry has made a big step forward providing access to the frequency dependence of the spin-lattice relaxation in all kinds of soft matter. The frequency dependence directly reflects the molecular dynamics. Most FC studies focus on protons. Due to the multi-particle character of the relevant interaction a super-position of molecular reorientation and translation is probed, which often hampers quantitative insights. In contrast, deuteron FC NMR solely detects reorientation and, hence, theoretical understanding and computer simulation are strongly facilitated. One also profits from the isotope selectivity of NMR which allows data to be interpreted in a much more specific way as compared to other methods. However, as the deuteron NMR frequency is small, current FC relaxometers are not suitable for routine FC NMR studies. Rather, a new generation of relaxometers has to be developed. A combination of quickly switching thousands of amperes in a sophistically designed coil system and reaching a strong magnetic field of high accuracy make the task very demanding. It is the aim of the present project to achieve this and to make deuteron FC NMR a routine technique of “molecular rheology”. Likewise, investigations of other nuclei such as 7Li, 13C, and 31P will become possible, and even proton relaxometry will strongly benefit.