Relaxation Effects in Nuclear Magnetic Resonance Absorption
Relaxation Effects in Nuclear Magnetic Resonance Absorption
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DOI：
10.1142/9789814540223_0039
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发表时间：
1948-04
期刊：
影响因子：
--
通讯作者：
N. Bloembergen;E. Purcell;R. Pound
中科院分区：
文献类型：
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作者：
N. Bloembergen;E. Purcell;R. Pound
强磁场中的核自旋系统与含有磁核的物质的其他自由度(“晶格”)组成的热库之间的能量交换，有助于使自旋系统在有限的温度下达到平衡。在这种情况下，系统可以从施加的射频场中吸收能量。但是，随着能量的吸收，自旋温度有升高的趋势，吸收速率有下降的趋势。通过这种“饱和”效应，以及在某些情况下用更直接的方法，可以测量自旋晶格弛豫时间${T}{1}$。磁核之间的相互作用对吸收谱线的宽度有贡献，其特征时间为{T_2}^{}{}_}{}^‘}}。这两种相互作用已经在各种物质中进行了研究，但重点是在含有氢的液体中。
The exchange of energy between a system of nuclear spins immersed in a strong magnetic field, and the heat reservoir consisting of the other degrees of freedom (the "lattice") of the substance containing the magnetic nuclei, serves to bring the spin system into equilibrium at a finite temperature. In this condition the system can absorb energy from an applied radiofrequency field. With the absorption of energy, however, the spin temperature tends to rise and the rate of absorption to decrease. Through this "saturation" effect, and in some cases by a more direct method, the spin-lattice relaxation time ${T}_{1}$ can be measured. The interaction among the magnetic nuclei, with which a characteristic time $T_{2}^{}{}_{}{}^{\ensuremath{'}}$ is associated, contributes to the width of the absorption line. Both interactions have been studied in a variety of substances, but with the emphasis on liquids containing hydrogen.