We describe a useful method for measuring the internuclear distances within arbitrarily selected pairs of like nuclei in dipolar-coupled multi-spin systems. The method uses a combination of the zero-quantum shift-evolution-assisted selective homonuclear recoupling (ZQ-SEASHORE) technique developed by Hu and Tycko [J. Chem. Phys. 2009, 131, 045101] and double-frequency-selective radio-frequency pulse. The double-frequency-selective pulse inverts polarizations of two spins simultaneously, and thus applications of the method presented here are only limited by the spectral resolution, and not by the number of interacting spins. Our experiments demonstrate the validity of the method and present analytical expressions for the dephasing curve.

我们描述了一种有用的方法，用于测量偶极耦合多自旋系统中任意选择的相似核对之间的核间距。该方法结合了由Hu和Tycko开发的零量子位移演化辅助选择性同核再结合（ZQ-SEASHORE）技术。物理学。2009，131，045101]和双频选择射频脉冲。双频选择脉冲同时反转了两个自旋的极化，因此此处介绍的方法的应用仅受频谱分辨率的限制，而不受相互作用的自旋数的限制。我们的实验证明了该方法的有效性，并给出了移相曲线的解析表达式。