 Electron paramagnetic resonance

Electron Paramagnetic Resonance (EPR), also known as Electron Spin Resonance (ESR), is a spectroscopic technique used to study materials that have unpaired electrons. These unpaired electrons can originate from a variety of sources, including free radicals, transition metal complexes, and certain types of defects in solids. ### Key Principles: 1. **Magnetic Moments**: Unpaired electrons possess a magnetic moment due to their spin, allowing them to interact with magnetic fields.