Supporting information: Dynamic Nuclear Polarization Mechanisms using TEMPOL and trityl OX063 radicals at 1 T and 77 K

Additional 1H and 13C NMR data is provided in the Supplementary Information, supporting the absolute enhancement factor calculations. This includes 1H and 13C saturation recovery buildup curves from which the 1H and 13C buildup rates in the presence of TEMPOL and trityl OX063 are determined. Detailed DNP spectra are also presented, highlighting the three-spin solid effect in 1H for trityl OX063, as well as extra information on the methyl rotor-induced cross-relaxation 13C DNP optima. Furthermore, additional EPR data is provided, including electron spin-lattice and spin-spin relaxation buildup and decay curves for TEMPOL.