Spin coherence in crystalline complexes. Naphthalene: 2(1,4-diiodotetrafluorobenzene)

The weak crystalline complex of naphthalene : 2(1,4-diiodotetrafluorobenzene), which exhibits naphthalene phosphorescence with a lifetime in milliseconds, is conveniently investigated by a combination of conventional and pulse techniques of optically detected magnetic resonance. The D + E and D - E resonances, investigated here, reveal no transferred hyperfine interaction, but increased D and E values because of the external spin-orbit coupling which is found to be anisotropic. Measurements are made of T₂, T₂*, and T₂ρ{variant} for this complex. This coherence study finds T₂ to be similar in magnitude to what has been observed for mixed organic crystals. T₂*, when compared with T₂, confirms the earlier suggestion that the crystalline complex is highly ordered. T_2ρ{variant} measurement suggests interaction with the nuclear spins of C₆I₂F₄.