Molecular Relaxation by ESR Spectroscopy and Related Phenomena

Jack H.博士康奈尔大学的Freed因其通过ESR光谱学进行分子弛豫和相关现象的研究而获得化学系物理化学项目的资助。 将继续研究复杂流体中的动态分子过程和结构。 新的二维傅立叶变换（2D-FT）ESR，包括电子-电子双共振（2D-ELDOR），远红外（FIR）ESR技术和伴随的理论发展将被用来研究在9至250 GHz的制度在液体中的旋转分子动力学。 特别是，动态笼模型将进行测试，特别是在玻璃形成液体的情况下。这些方法也将被应用于研究氩基质中甲基自由基在40 K以下自旋弛豫的量子转动性质。 将使用扩散动态成像（DID）-ESR测量宏观扩散和2D-ELDOR微观扩散的液体中的微观和宏观平移扩散的比较。 新的双量子相干（DQC）-ESR方法将被开发用于测量有机双自由基中的距离，以及双标记聚合物中的距离分布。 流体结构的检测和分析仍然是物理化学的一个具有挑战性和重要性的领域，并且是许多重要化学过程的关键。 Freed博士在康奈尔大学的实验室将继续扩展ESR光谱的实用性，以分析复杂液体（如聚合物溶液）中的扩散过程。 这些研究所提供的进步在该学科中提供了技术领导，并影响了许多其他实验室。 所提供的结果将扩展我们对液体结构和溶液结构的理解。

Dr. Jack H. Freed of Cornell University is funded for his research on molecular relaxation by ESR spectroscopy and related phenomena by the Physical Chemistry Program of the Chemistry Division. Studies of dynamic molecular processes and structure in complex fluids will be continued. New two-dimensional Fourier transform (2D-FT) ESR, including electron-electron double resonance (2D-ELDOR), and far infrared (FIR) ESR techniques and accompanying theoretical developments will be employed to study rotational molecular dynamics in liquids over the 9 to 250 GHz regime. In particular, the dynamic cage model will be tested, especially in the context of glass-forming liquids. These methods also will be applied to the study of the quantum rotational nature of spin relaxation in argon matrix trapped methyl radicals below 40K. Comparisons of microscopic and macroscopic translational diffusion in liquids will be made using dynamic-imaging of diffusion (DID)-ESR for the measurement of macroscopic diffusion and 2D-ELDOR for microscopic diffusion. The new double-quantum coherence (DQC)-ESR method will be developed for the measurement of distances in organic biradicals, and for distance distributions in bilabeled polymers. The detection and analysis of structure in fluids remains a challenging and important area of physical chemistry and is key to many important chemical processes. Dr. Freed's laboratory at Cornell Unviersity will continue extending the utility of ESR spectroscopy to the analysis of diffusion processes in complex liquids (such as polymeric solutions). The advances provided by these studies provide technical leadership in the discipline, and impact many other laboratories. The results to be provided will extend our understanding of liquid structure and of solution structure.