Electron paramagnetic resonance

For the dating technique, see Electron spin resonance dating.

Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spins excited are those of the electrons instead of the atomic nuclei. EPR spectroscopy is particularly useful for studying metal complexes and organic radicals. EPR was first observed in Kazan State University by Soviet physicist Yevgeny Zavoisky in 1944,[1][2] and was developed independently at the same time by Brebis Bleaney at the University of Oxford.

Typical set-up for recording EPR spectra. The user would be seated next to the RF generator, magnet, and controls for sample temperature. Bruker ELEXSYS E500 EPR instrument from NYU.
  1. ^ Zavoisky E (1945). "Spin-magnetic resonance in paramagnetics". J. Phys. (USSR). 9: 245.
  2. ^ Zavoisky E (1944). Paramagnetic Absorption in Perpendicular and Parallel Fields for Salts, Solutions and Metals (PhD thesis).