TRANSFERT PHOTOINDUIT DE PROTONS DANS DES CRISTAUX MIXTES PENTACENE/ACIDE BENZOIEQUE CARACTERISE PAR SPECTROSCOPIE OPTIQUE

摘要

Several phototransformations in condensed molecular phases at low temperatures are based on hydrogen photoinduced motions. Beyond its potential use for optical memories, the hydrogen motion in organic solids at low temperature has become an important topic over the past decade in holebuming spectroscopy. Carboxylic acid crystals doped with dye molecules offer model systems for studies of hydrogen motions. For pentacene dissolved in molten deuterated benzoic acid a proton-deuterium exchange between the solvent and solute molecules is observed at 125℃. Since the spectral lines corresponding to different partially deuterated species of pentacene in the benzoic acid host are well separated in the low temperature spectrum, the reaction is monitored by recording at 1.6 K the visible absorption spectra of dye. Obtention of selective deuterated pentacene has opened the most useful results to understanding of the photoreaction mechanism.