A primer in pulse EPR-based hyperfine spectroscopy for NMR spectroscopists

The theoretical foundations of NMR and EPR are very similar. Nevertheless, the fields differ significantly in practical aspects. This primer is an attempt to bridge some of the gaps between the fields, and at the same time it highlights some applications of pulse EPR. Basic EPR pulse sequences to detect nuclei in the vicinity of unpaired electrons are introduced. An emphasis is placed on explaining the concept to researchers familiar with NMR. The theoretical background as well as examples are given for electron-nuclear double resonance (ENDOR), electron-spin echo envelope modulation (ESEEM), including hyperfine sublevel correlation spectroscopy (HYSCORE), and electron double resonance (ELDOR)-detected NMR.