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.