Published Paper Details:

A form of magnetic resonance spectroscopy, Electron Paramagnetic Resonance (EPR), or Electron Spin Resonance (ESR), uses microwave radiation to probe unpaired electrons, such as radicals, radical cations and triplets in the presence of an externally induced static magnetic field. There are significant similarities between EPR and NMR in terms of their physical characteristics (NMR). Electron spin characteristics are directly measured in EPR, as opposed to nuclear spins, in NMR, the most noticeable distinction. As long as you have unpaired electron spins, EPR spectroscopy may be used in a number of ways, from examining extremely reactive radical intermediates to finding out how paramagnetic metal clusters interact with bioenzymes. EPR may also be employed in the semiconductor sector to analyse materials containing conducting electrons. Biological applications of electron paramagnetic resonance (EPR) spectroscopy include radicals and transition metal ion complexes having one or more unpaired electrons. Understanding the fundamental phenomena of spectroscopy, such as electronic Zeeman interaction, resonance, anisotropy, saturation, hyperfine interaction and zero-field interactions is covered in this chapter. Spectral powder pattern from randomly oriented samples is discussed, and a simulation method based on unit-sphere walking is presented. Spin counting or quantitative EPR is also discussed in connection to the concept of effective spins, which are physiologically important.