Electron-electron double resonance study of trapped electrons in 10M NaOH alkaline ice glass

Electron‐electron double resonance (ELDOR) has been used to test the validity of the noninteracting spin‐packet model for inhomogeneously broadened electron paramagnetic resonance (EPR) lines as applied to trapped electrons in 10M NaOH ice. Spectral simulation of field‐swept ELDOR spectra based on the spin‐packet model qualitatively, but not quantitatively, accounts for the observed spectra. The quantitative failure of the spin‐packet model is interpreted in terms of spin diffusion within the EPR line. Structure in frequency‐swept ELDOR spectra, which is not predicted by the spin‐packet model, has been observed and interpreted as $\text{∼ 5.7}\mathrm{G}$ hyperfine coupling with eight matrix protons. This supports a tetrahedral model of oriented water dipoles for the immediate environment of the trapped electron in alkaline ice.