EFFECT OF PRESSURE AND TEMPERATURE ON THE H-ATOM TUNNELING IN SOLID-PHASE CHEMICAL-REACTIONS - THE ACRIDINE FLUORENE SYSTEM/

In this paper the influence of temperature and pressure on the rate co nstant of photosensibilized tunneling of a hydrogen atom in an 'acridi ne-fluorene' system is considered. The influence of various types of v ibrations on the temperature dependence of the hydrogen transfer rate constant is studied. Published experimental data on the temperature an d pressure dependence are treated in terms of a modified theory of rad iationless transitions. The reduction of equilibrium intermolecular di stances and the frequency increase of the promotive modes under the ef fect of the applied external pressure are taken into account. The H/D isotope effect of the investigated reaction is considered. The literat ure data for the dependence 'volume vs. pressure' in aromatic single c rystals are utilized for the interpretation of experimental results. ( C) 1998 Elsevier Science B.V. All rights reserved.