Direct measurement of the triple spin flip rate in dynamic nuclear polarization

A previous study of the effect of Gadolinium doping on the dynamic polarization (DNP) of C-13 using trityls showed that the rate at which the polarization builds up is almost independent of the Gadolinium concentration, while the electron spin-lattice relaxation rate varies over an order of magnitude. In this paper we analyze the polarization build-up in detail and show that in this case DNP is due to the cross-effect (CE) and that the build-up rate can be quantitatively interpreted as the rate of the triple spin flips responsible for the CE. Thus this build-up rate presents a direct measurement of this triple spin flip rate. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The effect of Gadolinium doping on the dynamic polarization (DNP) of C-13 has been studied, revealing that the rate at which polarization builds up is largely independent of the Gadolinium concentration. On the other hand, the electron spin-lattice relaxation rate varies significantly. The analysis indicates that DNP in this case is primarily due to the cross-effect (CE) and the build-up rate is a direct measurement of the triple spin flip rate responsible for the CE.