The process of DNP involves the use of electron spin polarization, which is transferred to nuclear spins through microwave irradiation. Typically, a polarizing agent, such as a stable free radical, is introduced to the sample. The sample is then irradiated with microwaves at a frequency that matches the electron spin resonance (ESR) condition, facilitating the transfer of polarization from electrons to nuclei. This results in a substantial enhancement of the NMR signal.
