Cross effect/thermal mixing

Continuous wave DNP polarization-transfer mechanisms can be generally classified into four fields, namely the Overhauser Effect (OE), the Solid Effect (SE), the Cross Effect (CE), and Thermal Mixing (TM). They have all been successfully applied to both solid and liquid samples. It is reported that many DNP applications have been performed at low magnetic fields based on these different polarization effects. 

The Cross Effect mechanism is based on allowed transitions and involves the interaction of electron spin packets in an inhomogeneously broadened EPR line. A similar effect, found in a homogeneously broadened EPR line, is called thermal mixing. Wollan proposed a method to process the intermediate case of... 

DNP in the solid state, via the solid effect (SE) can be traced back to Potmd [24], Abragam [25] and Jeffries [26]. Borghini described DNP in a spin temperature model [27, 28], which led to the discovery of thermal mixing (TM) [29]. In 1963 [30, 31], the cross effect (CE) was described, and later verified by Hwang, Hill [32, 33] and Wollan [34, 35]. In the following years, major work was carried out by Wind and coworkers [36]. Hausser and Stehlik derived the framework for DNP in... 

The thermal-induced intramolecular electron transfer rates of mixed-valence biferrocene monocation (Fe(II),Fe(III)) were determined in seven solvents and at various temperatures by the proton paramagnetic relaxation measurements. The rate constants of pico-second order were obtained at 298 K and the frequency factors showed a solvent dependence. The effect of solvent friction on the barrier crossing in the reaction trajectory was examined in the strong adiabatic regime. 

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