Solid-state NMR is a valuable tool for elucidating the structures and dynamics of materials at an atomic level. Proton multiple-quantum (MQ) /single-quantum (SQ) correlation NMR spectroscopy is widely used to probe spatial proximity among protons. In the triple-quantum (TQ)/SQ correlation experiment, the excitation of triple-quantum (TQ) coherences is traditionally achieved by a 90° pulse in conjugation with double-quantum (DQ) recoupling sequences. Nevertheless, such sequences often suffer from low TQ filtering efficiency and may lead to overlapping spinning sidebands in the indirect TQ dimension, especially at a slow MAS frequency. Herein, we design several supercycled symmetry-based RN_n^ν γ-free TQ recoupling sequences and compare their performance via extensive numerical simulation and experiments. Experimental results further confirm that $\left(R{18}_1^{6}R{18}_1^{-6}\right)3^1$ pulse sequence gives the highest TQ filtering efficiency of around 20% in the slow MAS regime (∼10 kHz). The 2D TQ/SQ spectrum at slow MAS is completely free of spinning sidebands in the TQ dimension due to its γ-free nature. We establish that such a γ-free $\left(R{18}_1^{6}R{18}_1^{-6}\right)3^1$ pulse sequence is a superior candidate for TQ spectroscopy at slow MAS frequency.

固态核磁共振是在原子水平上阐明材料结构和动力学的重要工具。质子多量子 (MQ) / 单量子 (SQ) 相关核磁共振光谱被广泛用于探测质子之间的空间接近度。在三量子 (TQ)/SQ 相关实验中，三量子 (TQ) 相干性的激发传统上是通过与双量子 (DQ) 重新耦合序列共轭的 90° 脉冲来实现的。然而，这样的序列通常会受到低 TQ 滤波效率的影响，并可能导致在间接 TQ 维度中重叠旋转边带，尤其是在慢 MAS 频率下。在这里，我们设计了几个基于超循环对称性的RN _n ^νγ-free TQ 重新耦合序列，并通过广泛的数值模拟和实验比较它们的性能。实验结果进一步证实$\left(\mathrm{电阻}{18}_1^6\mathrm{电阻}{18}_1^{-6}\right)3^1$脉冲序列在慢 MAS 状态（~10 kHz）中提供约 20% 的最高 TQ 滤波效率。由于其不含 γ 的性质，慢速 MAS 的 2D TQ/SQ 谱在 TQ 维度上完全没有自旋边带。我们确定这样一个无 γ$\left(\mathrm{电阻}{18}_1^6\mathrm{电阻}{18}_1^{-6}\right)3^1$ 脉冲序列是低 MAS 频率下 TQ 光谱的最佳候选者。