Grant for Exploratory Research: Field Cycling Electron Nuclear Double Resonance Studies

Alvin L. Kwiram教授得到了实验物理化学项目探索性研究的小额资助，以研究执行零场电子自旋共振（ESR）光谱的潜力。如果他成功了，这项新技术将比传统的ESR方法在研究有机自由基的结构和动力学方面提供许多独特的优势。零场核磁共振（NMR）技术已经问世一段时间了。与传统的核磁共振相比，它的主要优点是能够测量小的核四极耦合常数以及自旋半核的非常小的分裂。Kwiram计划采用快速电子开关技术来实现ESR的现场循环。电子开关是必要的，而不是机械方法采用的零场核磁共振波谱，因为在典型的ESR实验中遇到更短的弛豫时间。如果成功，由此产生的零场ESR应该比传统方法的灵敏度提高大约两个数量级。这种灵敏度的提高将为一些涉及基质分离物种和生物分子研究的新实验开辟可能性。

Professor Alvin L. Kwiram is supported by a Small Grant for Exploratory Research from the Experimental Physical Chemistry Program to investigate the potential for performing zero field electron spin resonance (ESR) spectroscopy. If he succeeds, this new technique will offer many unique advantages over conventional ESR methodologies for studying structure and dynamics of organic free radicals. Zero field nuclear magnetic resonance (NMR) techniques have been known for some time now. The primary advantage over conventional NMR, which arises from increased sensitivity, is the capability of measuring small nuclear quadrupole coupling constants as well as very small splittings of spin half nuclei. Kwiram plans to employ rapid electronic switching techniques to implement field cycling for ESR. Electronic switching is necessary rather than the mechanical methods employed in zero field NMR spectroscopy, because of the much shorter relaxation times encountered in typical ESR experiments. If successful, the resulting zero field ESR should have a sensitivity enhancement over conventional methods of about two orders of magnitude. This increased sensitivity will open up the possibility of a number of new experiments involving studies of matrix isolated species and biological molecules.