EPR Hyperfine Splitting in Organic Radicals

Electron paramagnetic resonance (EPR) spectroscopy can show how an unpaired electron behaves in an organic radical. A simple radical may give a single peak because the electron moves between two spin energy states.

In many radicals, the unpaired electron also interacts with nearby spin-active nuc...

A free unpaired electron would ideally lead to a single peak in the EPR spectrum resulting from the transition between two spin energy states.

However, in the presence of neighboring spin-active nuclei, the spectrum shows hyperfine splitting due to coupling between the electronic spin and nuclear spin.

The number of peaks obtained ...