组合脉冲宽带激发~2H-平均哈密顿理论计算研究（英文）

Theoretical Calculation of a Composite Pulse with 8-Step Phase Cycling for ~2H Broadband Excitation by Average Hamiltonian Theory

四级核回波实验通常需要射频脉冲能够激发谱宽超过100 k Hz的信号.在最近的研究中,作者发现组合脉冲COM-II(9018090135 45)能够在氘核的四级核回波实验中实现宽带激发.此外,作者还结合了八步相位循环的方法,有效消除了由有限脉宽效应造成的谱图扭曲现象.利用了平均哈密顿原理,对该方法进行了理论计算研究.作者采用了自旋为1的矩阵算符,通过计算解释了八步相位循环能够消除谱图扭曲的原因.

Quadrupolar echo NMR spectroscopy of solids often requires RF pulse excitation that covers spectral widths exceeding 100 kHz. In a recent work we found out that a composite pulse COM-II（901809013545）,provided robust broadband excitation for deuterium quadrupolar echo spectroscopy. Moreover, when combined with an 8-step phase cycle, spectral distortions arising from finite pulse widths were greatly suppressed. In this paper we report on a theoretical analysis of COM-II with 8-step phase cycle by average Hamiltonian theory. This treatment is combined with the fictitious spin-1 operator formalism, and the mechanism of the 8-step phase cycling that minimizes the spectral distortions is discussed.