Bussandri AP, Zuriaga MJ
Facultad de Matemática Astronomia y Fisica, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, 5000, Argentina
J Magn Reson. 1998 Apr;131(2):224-31. doi: 10.1006/jmre.1998.1363.
A theoretical description of nuclear spin-echo Fourier-transform mapping spectroscopy (NSEFTMS) for broad NQR lines is derived from the time-domain spin-echo theory for a spin I = 32 system. The expression found for the effective broadband RF excitation profile is similar to that in NMR spectroscopy. The main difference is the angular dependence of the nutation frequency, but this does not change the overall behavior. It is also shown that the maximum of the spin echo occurs at time t = tau + 2 2pitw1 after the second pulse, and that if the signal is acquired from this point, the phase-adjustment problem due to the off-resonance effect is avoided. A study of 35Cl NQR broad lines in molecular alloys of (p-dichlorobenzene)(1-x) (p-dibromobenzene)x at different temperatures and in the incommensurate phase of bis-(4-chorophenyl) sulfone at 77 K has been used as an example of the application of the method. The NSEFTMS method in NQR provides an efficient alternative to the time-consuming point-by-point scanning technique for the study of broad lines in solids, in particular when some sharp features exist. Copyright 1998 Academic Press.
基于自旋I = 3/2系统的时域自旋回波理论，推导了用于宽NQR线的核自旋回波傅里叶变换映射光谱学（NSEFTMS）的理论描述。所得到的有效宽带射频激发轮廓的表达式与核磁共振光谱学中的相似。主要区别在于章动频率的角度依赖性，但这并不改变整体行为。还表明，自旋回波的最大值出现在第二个脉冲之后的时间t = τ + 2 / 2πω1处，并且如果从这一点采集信号，则可以避免由于失谐效应引起的相位调整问题。以不同温度下（对二氯苯）(1 - x)（对二溴苯）x分子合金中的35Cl NQR宽线以及77 K下双（4 - 氯苯基）砜的非公度相为例，研究了该方法的应用。NQR中的NSEFTMS方法为研究固体中的宽线提供了一种有效的替代方法，可替代耗时的逐点扫描技术，特别是当存在一些尖锐特征时。版权所有1998年学术出版社。
