https://scholars.lib.ntu.edu.tw/handle/123456789/177691
標題: | Separation and characterization of different signals from intermolecular three-spin orders in solution NMR | 作者: | Chen, Zhong Chen, Zhi-Wei Hwang, Dennis W. Zhong, Jianhui Hwang, Lian-Pin |
關鍵字: | Intermolecular dipolar interactions;Multiple-quantum coherences;Three-spin order;Diffusion;Relaxation | 公開日期: | 2004 | 出版社: | Taipei:National Taiwan University Dept Chem Engn | 起(迄)頁: | - | 來源出版物: | Journal of Magnetic Resonance (171),244–252 | 摘要: | In this paper, signals originating from a pure specific coherence of intermolecular three-spin orders were separated & characterized experimentally in highly polarized two-component spin systems. A modified CRAZED sequence with selective radio-frequency excitation was designed to separate the small signals from the strong conventional single-spin single-quantum signals. General theoretical expressions of the pulse sequence with arbitrary flip angle pulses were derived using dipolar field treatment. The expressions were used to predict the relaxation & diffusion properties & optimal experimental parameters such as flip angles. For the first time, relaxation & diffusion properties of pure intermolecular single-quantum, double-quantum, & triple-quantum coherences of three-spin orders were characterized & analyzed in one-dimensional experiments. All experimental observations are in excellent agreement with the theoretical predictions. The theoretical results show that the quantum-mechanical treatment leads to exactly the same predictions as the dipolar field treatment. The quantitative study of intermolecular multiple-quantum coherences of three-spin orders presented herein provides a better understanding of their mechanisms. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/2006111501275431 | 其他識別: | 246246/2006111501275431 |
顯示於: | 化學系 |
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