Electron Nuclear Double Resonance of Photoexcited Anthracene Molecules in Their Lowest Triplet State in Phenazine Single Crystals

The electron paramagnetic resonance and proton electron nuclear double resonance spectra of anthracene molecules in their lowest energy photoexcited states in a single crystal of phenazine have been studied. The values of the fine structure parameters and of the components of the proton electron hyperfine interaction tensors, in the fine structure principal axis system, have been determined and tabulated. The values of spin densities and of anisotropic and isotropic proton hyperfine interactions per unit spin density on the adjacent carbon, which best describe the experimental results, have been determined, discussed, and compared with similar values for other systems.