Pannier M, Veit S, Godt A, Jeschke G, Spiess H W
Max-Planck-Institut für Polymerforschung, Mainz, 55021, Germany.
J Magn Reson. 2000 Feb;142(2):331-40. doi: 10.1006/jmre.1999.1944.
A four-pulse version of the pulse double electron-electron resonance (DEER) experiment is presented, which is designed for the determination of interradical distances on a nanoscopic length-scale. With the new pulse sequence electron-electron couplings can be studied without dead-time artifacts, so that even broad distributions of electron-electron distances can be characterized. A version of the experiment that uses a pulse train in the detection period exhibits improved signal-to-noise ratio. Tests on two nitroxide biradicals with known length indicate that the accessible range of distances extends from about 1.5 to 8 nm. The four-pulse DEER spectra of an ionic spin probe in an ionomer exhibit features due to probe molecules situated both on the same and on different ion clusters. The former feature provides information on the cluster size and is inaccessible with previous methods.
本文介绍了一种四脉冲版本的脉冲双电子-电子共振（DEER）实验，该实验旨在测定纳米尺度上的自由基间距离。利用新的脉冲序列，可以在没有死时间伪影的情况下研究电子-电子耦合，从而能够表征电子-电子距离的广泛分布。在检测周期中使用脉冲串的实验版本具有更高的信噪比。对两个已知长度的氮氧双自由基进行的测试表明，可测量的距离范围约为1.5至8纳米。离子聚合物中离子自旋探针的四脉冲DEER光谱显示出特征，这是由于探针分子既位于相同的离子簇上，也位于不同的离子簇上。前一种特征提供了有关簇大小的信息，而以前的方法无法获得这些信息。
