分子内和分子间双量子相干信号随预备期的变化规律

Variations of Intra-and Inter-molecular Double-quantum Coherences with Preparation Period

设计简化的三脉冲序列,研究高极化液体核磁共振中同核自旋体系中的分子内与分子间双量子相干信号随预备期的变化规律,有助于更深入地理解分子内与分子间双量子相干的性质与机理,为分离检测二者提供理论和实验依据.首先对普适的同核二自旋IpSq(p,q=1,2,3,…)体系进行理论推导,得到分子内与分子间多量子相干信号与预备期的关系表达式,并利用6种不同的自旋体系进行实验验证,实验结果与理论推导结果相当吻合.这种方法还可以扩展到异核自旋体系中,对分子结构的研究具有重要的意义.

A three-pulse sequence was designed to investigate the variations of intra- and inter-molecular double-quantum coherences with preparation period. It will help to better understand the properties and mechanism of intra- and inter-molecular multiple-quantum coherences. IpSq （p, q= 1,2, 3,……） spin system were focused to deduce the theoretical relations between different signals and preparation periods. Furthermore, six spin systems were used to verify the theoretical results. The experimental observations are matched well with the analytical expressions. The method proposed herein will be extended to heteronuclear cases. It may find potential application in molecular structure research.