Electron spin resonance (some chemical applications)

The field of ESR (or EPR) continues apace, predominantly as further applications are discovered for the method. As in all aspects of modern life, some of the greatest advances in the area of ESR and free-radical (paramagnetic) chemistry have arisen through the immense developments made in computing, and so we may witness not only supplements in instrumentation, e.g. pulsed ESR and ENDOR/TRIPLE methods, but also in theoretical techniques, most strikingly through the agency of Density Functional Theory (DFT), which, reminded of my early adventures with semi-empirical methods such as INDO, now appear to accurately reproduce experimental hyperfine coupling constants (always a challenging task for “open-shell” systems), and the energetics of paramagnetic molecular configurations.