Vibration‐assisted intermolecular hydrogen tunneling in photoreactive doped molecular crystals: Effect of temperature and pressure

Abstract

Abstract The pressure and temperature dependence of the reaction rate of the photochemical intermolecular H‐transfer reaction in acridine‐doped fluorene single crystals exhibit all typical features of solid state H‐tunneling. Independent Raman data including the pressure dependence have identified three low energy inter‐ and intramolecular vibrational fluctuations as reaction promoting modes. The mode identification allows a more subtle analysis of the H‐transfer reaction rate behavior on the basis of recent theoretical concepts. Surprisingly, the complete data set k (P, T) can be satisfactorily reproduced by an average one frequency mode model with parameters consistent with an average of the parameters calculated for the individual reaction promoting modes.