TRANSIET NUCLEAR INDUCTION AND DOUBLE NUCLEAR RESONANCE IN SOLIDS
TRANSIET NUCLEAR INDUCTION AND DOUBLE NUCLEAR RESONANCE IN SOLIDS
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DOI：
10.1103/physrev.103.148
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发表时间：
1956-01-01
期刊：
影响因子：
--
通讯作者：
HAHN, EL
中科院分区：
文献类型：
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作者：
HERZOG, B;HAHN, EL
基于马尔可夫过程的随机模型描述了固体产生的瞬变核感应信号的行为。该模型假定晶体中存在由一组耦合核B引起的局域偶极场涨落。这些涨落可以破坏或增强观察到的晶体中不同A组原子核的进动一致性。假设A自旋之间的耦合可以忽略不计。在给定时间t形成的A的自旋回波具有由场起伏的幅度和速率R确定的幅度。当RT介于零和单位数量级之间时，回波幅度减小，在RT∼1时达到最小值，而在RT>；1时增加。对于以频率为单位的R大于自旋A静态线宽(当R=0时)，线变窄有效，并且通过增加的寿命和回波信号的幅度来反映。研究了核四极体系NaCl3中B自旋(Na2 3)连续波共振对A(Cl3 5)回波弛豫的影响.对于Na2 3足够弱的CW RF激发，Cl3 5回波的行为大致遵循局域场涨落速率R变化的随机模型所预测的行为.讨论了在较大的CW RF激发下局域场的相干振荡效应.用双共振法研究了Na2 3四极共振的塞曼分裂。由于分子扩散，液体中自旋回波信号的衰减可以方便地用随机模型来描述。
The behavior of transient nuclear induction signals from solids is described by a stochastic model based on a Markoff process. The model assumes the presence of local dipolar field fluctuations in a crystal due to a set B of coupled nuclei. These fluctuations can destroy or enhance the observed precessional coherence of a different set A of nuclei in the crystal. Coupling among A spins is assumed negligible. The spin echo of A formed at a given time t has an amplitude determined by the magnitude and rate R of field fluctuations. For values of Rt between zero and the order of unity the echo amplitude decreases, reaches a minimum at Rt∼ 1, and increases for Rt> 1. For R larger than the spin A static line width (when R= 0) in units of frequency, line narrowing becomes effective, and is reflected in terms of increased lifetime and amplitudes of echo signals. The effect of B spin (Na 23) continuous wave resonance upon the echo relaxation of A (Cl 35) is studied in NaCl O 3, a nuclear quadrupole system. For sufficiently weak cw rf excitation of Na 23, the behavior of Cl 35 echoes roughly follows the behavior predicted by the stochastic model for changes in local field fluctuation rate R. The effect of coherent oscillations of local fields at larger cw rf excitation is discussed. Zeeman splittings of the Na 23 quadrupole resonance are studied by the double resonance method. The decay of spin echo signals in liquids, as a result of molecular diffusion, is conveniently described by the stochastic model.