Electron Spin–Spin Interactions in DNP: Thermal Mixing vs. the Cross Effect

The spectrum of the electron spin–spin interactions largely determines mechanism that governs dynamic nuclear polarization (DNP). A narrow favors solid effect (SE). broader brings cross (CE) into play—that is an exchange Zeeman energy with spins—and a very broad also thermal mixing (TM)—that interaction spins. previous article described Monte Carlo simulations these for approximately spherical radicals in glasses and showed this best by Lorentzian smoothly cut-off Gaussian. That work provided analytical approximations lower moments width Gaussian cut-off. Here we extend derivation approximation use result to determine relative strengths flows due CE TM as function diameter radicals, their concentration magnetic field.