Theory of Saturation and Double Resonance Effects in ESR Spectra. III. rf Coherence and Line Shapes
Theory of Saturation and Double Resonance Effects in ESR Spectra. III. rf Coherence and Line Shapes
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ESR 光谱中的饱和理论和双共振效应。
DOI：
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发表时间：
1967
期刊：
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通讯作者：
J. S. Hyde
中科院分区：
文献类型：
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作者：
J. Freed;D. S. Leniart;J. S. Hyde
自由基稀溶液的电子自旋共振谱中的饱和理论已被用来详细分析 ENDOR 谱中的几种可能的影响，这些影响是由于所应用的核射频和微波场的相干性质造成的。这些效应隐式地包含在“相干矩阵”中，尽管它们的观察也取决于松弛项的细节。结果表明，(1) 强核射频场可以分裂 ESR 线，这种现象类似于 NMR 双共振中的“自旋痒痒”，(2) 在存在较弱但饱和的核射频场的情况下，强微波场可以分裂 ENDOR 线，并且后一种效应已通过实验得到证明。仔细分析了一种微妙的相干效应，它需要 I>1/2 的核自旋，或者 I=1/2 的多个等效自旋，并且取决于核射频场强度。预计它只会显着影响通过使两个或四个等效 Pro 的 M = 0 超细线饱和而获得的 ENDOR 线。
The theory of saturation in the electron spin resonance spectra of dilute solutions of free radicals has been employed to analyze in detail several possible effects in ENDOR spectra that are due to the coherent nature of the applied nuclear rf and microwave fields. These effects are implicitly contained in a ``coherence matrix,' although their observation also depends on the details of the relaxation terms. It is shown that (1) strong nuclear rf fields can split ESR lines, a phenomenon similar to ``spin‐tickling' in NMR double resonance, (2) strong microwave fields in the presence of weaker, but saturating, nuclear rf fields can split ENDOR lines, and this latter effect is demonstrated experimentally. A subtle coherence effect requiring nuclear spins of I>½, or more than one equivalent spin of I=½, and dependent upon nuclear rf field strength is carefully analyzed. It is predicted to significantly affect only the ENDOR line obtained from saturating the M = 0 hyperfine line for two or four equivalent pro...