However, about a decade ago 2, 28, 29 and more recently in high field DNP experiments using trityl radicals, a dispersive DNP field profile was observed, , which is difficult to explain as TM. We believe this is because the trityl molecules are bulky, and the interaction between pairs cannot be much larger than about 50 MHz . Furthermore, in the Supporting Information (SI) we calculate the dipole sum for the case that generates the maximum possible electron spin frequency shift in a cluster and the electron frequency shift should be well below 600 MHz where we have performed experiments.