Theory of Spin Resonance and Relaxation
Theory of Spin Resonance and Relaxation
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自旋共振和弛豫理论
DOI：
10.1103/physrev.134.a98
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发表时间：
1964
期刊：
影响因子：
--
通讯作者：
P. Kelley
中科院分区：
文献类型：
--
作者：
P. Argyres;P. Kelley
本文提出了一种自旋共振和弛豫的量子统计力学理论，它避免了早期理论的假设，能够扩展到弛豫机制强度的最低玻恩近似之外的其他近似，并且适用于更广泛的物理情况。从自旋+浴的组合系统的刘维尔方程，该理论产生了一个非马尔可夫方程的时间发展的统计密度算符的自旋系统单独。详细考虑了自旋系统在驱动场中的线性响应，导出了稳态自旋密度算符方程。一个简单的应用阐明了该理论的新特点，并表明它描述了“运动”窄化现象。对任意外场的响应进行了研究，特别提到了接近热平衡的问题和自旋共振饱和现象。后者被认为是在一些详细的独立的自旋系统，其中的稳态磁化方程推导和讨论。
A quantum-statistical-mechanical theory of spin resonance and relaxation is presented, which avoids the assumptions of earlier theories, is capable of extension to other than the lowest Born approximation for the strength of the relaxation mechanism, and is applicable over a broader range of physical situations. From the Liouville equation for the combined system of spin+ bath, the theory yields a non-Markoffian equation for the time development of the statistical density operator for the spin system alone. Detailed consideration is given to the response of the spin system linear in the driving field, and an equation for the steady-state spin density operator is deduced. A simple application exemplifies the new features of the theory and it is shown that it describes the phenomenon of" motional" narrowing. The response to an arbitrary external field is studied with particular reference to the problem of approach to thermal equilibrium and the phenomenon of spin resonance saturation. The latter is considered in some detail for a system of independent spins, for which an equation for the steady-state magnetization is derived and discussed.