Double electron-electron resonance spectroscopy (DEER, also known as PELDOR) is used to study spin-spin dipolar interactions between spin labels, at the nanoscale range of distances. The DEER effect is obtained as a signal generated by echo-forming microwave (mw) pulses with an additional mw pump pulse applied at a different frequency. It is important to carry out measurements without artefacts induced by overlap of the pulses in the time scale. Such an experiment without the dead-time effect is achieved using the 4-pulse (4p) DEER method. The analysis of the literature performed here shows however that the 3-pulse (3p) DEER can also be free of the dead time problem, for which there are two possibilities. The first occurs using a specially designed bimodal resonator, for which the two frequencies are completely decoupled. The second possibility, which can be implemented for any commercial spectrometer, involves the signal correction based on an additional “blank” measurement with the pump pulse applied outside the EPR resonance. A detailed comparison of the 3p and 4p DEER data obtained previously by Milov et al. [Appl. Magn. Reson. 41 (2011) 59–67] shows that 3p and 4p approaches give similar results. The advantages of the 3p DEER techniques are discussed.

双电子-电子共振光谱（DEER，也称为 PELDOR）用于研究自旋标记之间在纳米级距离范围内的自旋-自旋偶极相互作用。DEER 效应是通过回声形成微波 (mw) 脉冲生成的信号获得的，附加的 mw 泵浦脉冲以不同的频率应用。重要的是在没有由时间尺度中脉冲重叠引起的人工制品的情况下进行测量。这种没有死区时间效应的实验是使用 4 脉冲 (4p) DEER 方法实现的。然而，此处执行的文献分析表明，3 脉冲 (3p) DEER 也可以避免死区时间问题，这有两种可能性。第一种是使用专门设计的双峰谐振器，两个频率完全解耦。第二种可能，可以为任何商业光谱仪实现，涉及基于额外“空白”测量的信号校正，泵脉冲在 EPR 共振之外应用。Milov 等人先前获得的 3p 和 4p DEER 数据的详细比较。[申请。马格尼。共鸣。41 (2011) 59–67] 显示 3p 和 4p 方法给出相似的结果。讨论了 3p DEER 技术的优点。