EPR Spectroscopy

Electron Paramagnetic Resonance (EPR) spectroscopy, also known as Electron Spin Resonance (ESR), is a powerful technique used to study systems that contain unpaired electrons, such as free radicals, transition metal ions, and defects in solids. It is based on the interaction of electron spins with an external magnetic field, where absorption of microwave radiation induces transitions between spin states. Because the electron has a much larger magnetic moment than the nucleus, EPR is highly sensitive to the local electronic environment, providing detailed information about electronic structure, geometry, and dynamics.

In chemistry, EPR is widely used to characterize transition metal complexes, identify and quantify radical intermediates, and probe reaction mechanisms, especially in catalysis and redox processes. It can reveal oxidation states, ligand environments, and spin distribution in paramagnetic species.

In biology, EPR plays a crucial role in studying metalloproteins (e.g., copper and iron centers), radical-containing enzymes, and membrane proteins. Using site-directed spin labeling (SDSL) in combination with continuous-wave EPR, local dynamics and flexibility of proteins and nucleic acids can be effectively probed. Furthermore, spin labeling coupled with advanced pulsed EPR techniques, such as DEER/PELDOR, enables the determination of long-range distance distributions and conformational changes in biomolecules, even in complex environments such as cells. Importantly, EPR is not limited by molecular size, making it equally applicable to small molecules as well as large macromolecular complexes.

EPR Books

Online Lectures by Prof. Daniella Goldfarb

EPR Simulation Tools and Softwares

Organization