What PELDOR is used forThere is a particular interest in double electron electron resonance (DEER) also known as pulsed electron-electron double resonance (PELDOR) due to the electron dipole interaction having a dependence on distance. This has been a growing area of interest particularly in the fields of biology and chemistry, beginning as a compliment to the heavily used Förster resonance energy transfer (FRET) technique DEER has become the go to tool for distance determination on biomolecular structures. The key advantage which spin labelled DEER experiments holds over FRET is the small footprint of the labels which need to be attached, typically much larger in FRET experiments. The distances which can be measurable with DEER are also much greater than those which can be measured using FRET.
It is also the case that the spin labels commonly used in PELDOR experiments have anisotropic effects, resulting in their resonances changing depending on how they are orientated in the main magnetic field.