Electron paramagnetic resonance (
EPR) and/or electron spin resonance (
ESR) is defined as the form of spectroscopy concerned with microwave-induced transitions between magnetic energy levels of electrons having a net spin and orbital angular momentum. The term electron paramagnetic resonance and the symbol
EPR are preferred and should be used for primary indexing.
Source:
PAC, 1989, 61, 2195. 'Recommendation for EPR/ESR nomenclature and conventions for presenting experimental data in publications (Recommendations 1989)' on page 2196 (https://doi.org/10.1351/pac198961122195)