三种脉冲序列制备核自旋单重态效率的比较

Preparation Efficiency of Nuclear Spin Singlet State:A Comparison Among Three Pulse Sequences

核自旋单重态的制备和检测在化合物分子的相关分析中具有重要的应用价值和广阔的应用前景.本文以三肽分子AGG(Ala-Gly-Gly)中两个质子构成的一组孤立的自旋耦合体系为研究对象,利用三组基于不同原理的脉冲序列,分别对该体系制备了核自旋单重态;并分别测定和比较了三种方法制备核自旋单重态的效率及其寿命.研究结果表明,对于同一分子的同一自旋耦合体系中的质子,使用不同的脉冲序列制备得到的核自旋单重态的寿命并不会有明显差异,但基于不同脉冲制备核自旋单重态的效率差异相对较大.

The preparation and detection of the nuclear singlet state are valuable and prospective for many applications related with compound molecular analysis.In this work,a proton spin coupled system containing two H nuclei in tripeptide(Ala-Gly-Gly,AGG)was selected as research object,and singlets were prepared with three sets of different pulse sequences based on different principles.The lifetime of those singlets were measured,and the singlet preparation efficiencies of different sequences were compared.The results indicated that for the same spin coupling system of the same molecule,there is no significant difference in the lifetime of the singlet state prepared by different pulse sequences,while their preparation efficiencies could be relatively different.