固态Photo-CIDNP效应

光化学诱导动态核极化(photo-CIDNP)是一种在光照条件下由于产生非玻尔兹曼核自旋极化而使核磁共振(NMR)波谱信号强度发生明显变化的效应。这种效应在液体NMR中已为人所熟知,并通过经典的自由基对机理得到解释。固态photo-CIDNP效应发现的较晚,本文介绍了在光合反应中心及蓝光受体中发现的固态photo-CIDNP效应,详细阐述了固态photo-CIDNP效应产生的自由基对自旋动力学的机理,包括三旋混合(TSM)、衰变差异(DD)和弛豫差异(DR),重点介绍了类球红杆菌光合反应中心固态photo-CIDNP效应的磁场依赖性,这种场依赖性在同一分子中的不同核之间表现出明显的差异。本文综述了固态photo-CIDNP效应的现象、理论及其磁场依赖特性的最新进展。

The Solid-State Photo-CIDNP Effect

Photochemically induced dynamic nuclear polarization (photo-CIDNP) is an effect that produces non-Boltzmann nuclear spin polarization, which can be observed as a modification of signal intensity in nuclear magnetic resonance (NMR) spectroscopy. The effect is well known in liquid-state NMR, where it is explained most generally by the classical radical pair mechanism (RPM). In the solid-state, additional mechanisms are operative in the spin-dynamics of radical pairs, such as three-spin mixing (TSM), differential decay (DD) and differential relaxation (DR). The observed solid-state photo-CIDNP effect is strongly magnetic field dependent, and this field-dependence is well distinguished for the various nuclei. Here, we provide an account of the phenomenology, theory and properties of the magnetic field dependence of the solid-state photo-CIDNP effect.