二维多量子MAS NMR的计算机模拟研究

波谱学杂志 ›› 1997, Vol. 14 ›› Issue (2): 127-134.

二维多量子MAS NMR的计算机模拟研究

李宝会¹, 金庆华¹, 陈铁红², 孙平川³, 郭振亚¹, 丁大同¹

1. 南开大学物理系, 天津 300071;
2. 南开大学化学系, 天津 300071;
3. 南开大学吸附分离功能高分子材料国家重点实验室, 高分子化学研究所, 天津 300071

收稿日期:1996-10-21 修回日期:1996-11-26 出版日期:1997-04-05 发布日期:2018-01-22
基金资助:
国家自然科学基金资助项目

COMPUTER SIMULATION OF THE 2D MULTIPLE-QUANTUM MAGIC-ANGLE SPINNING NMR

Li Baohui¹, Jin Qinghua¹, Chen Tiehong², Sun Pingchuan³, Guo Zhenya¹, Ding Datong¹

1. Department of Physics, Nankai University, Tianjin 300071;
2. Department of Chemistry, Nankai University, Tianjin 300071;
3. The State Key Laboratory of Functional Polymer Materials for Adsorption and Separation, Institute of Polymer Chemistry, Nankai UUniversity, Tianjin 300071

Received:1996-10-21 Revised:1996-11-26 Online:1997-04-05 Published:2018-01-22

摘要/Abstract

摘要： 最近Frydman等人报道了联合MAS及多量子方法获取半整数四极核各向同性谱的新途径,本文以自旋3/2的四极核为例,采用步进式时序积分手续,数值计算了魔角样品旋转条件下的传播子,从而真实地模拟了非对易含时Hamiltonian情况下的密度矩阵演化;对Fryman等人采用的双脉冲序列实验应采取的最佳条件进行了详尽的理论分析;并对Na₂C₂O₄样品的2D-MQ-MAS实验进行拟谱。

关键词: 半整数四极核, 二维多量子NMR, Na₂C₂O₄, 数值模拟

Abstract: Very recently, Frydman et al. have shown that the combined use of MAS and two-dimensional multiple-quantum (MQ) spectroscopy can refocus the second-order anisotropic effects of half-in-teger quadrupoles. The present paper discusses theoretical aspect of this novel 2D MQ MAS method through evaluating the propagation of density matrices evolving under the effects of noncommuting time-dependent Hamiltonians. The influence of radiofrequency pulse excitation and conversion on the intensities in the spectra is analyzed and the conditions that maximize the MQ MAS signal for a spin-3/2 are obtained. Numerical simulation of the 2D experimental spectrum of ²³Na of Na₂C₂O₄ shows that the quadrupolar coupling parameters and the isotropic chemical shift can be determined.

Key words: Half-integer quadrupolar nuclei, Two-dimensional multiple-quantum NMR, Na₂C₂O₄, Numerical simulation

李宝会, 金庆华, 陈铁红, 孙平川, 郭振亚, 丁大同. 二维多量子MAS NMR的计算机模拟研究[J]. 波谱学杂志, 1997, 14(2): 127-134.

Li Baohui, Jin Qinghua, Chen Tiehong, Sun Pingchuan, Guo Zhenya, Ding Datong. COMPUTER SIMULATION OF THE 2D MULTIPLE-QUANTUM MAGIC-ANGLE SPINNING NMR[J]. Chinese Journal of Magnetic Resonance, 1997, 14(2): 127-134.

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