Contributions of Exchange and Dipole–Dipole Interactions to the Shape of EPR Spectra of Free Radicals in Diluted Solutions

This report presents a comprehensive analysis of the contributions of the Heisenberg exchange and dipole–dipole interactions in diluted solutions of nitroxide radicals to the shape of their electron paramagnetic resonance (EPR) spectra taking into account all coherence transfer processes. It is shown that these contributions interfere. The approaches to obtain the molecular-kinetic and exchange integral parameters by analyzing the EPR spectrum dependence on the radical concentration and the solvent viscosity are discussed.