Decrease of threshold energy in photo-stimulated processes in condensed media

On the base of analysis, a great number of experiments related to the Staebler-Wronski effect in alpha -Si:H, we worked out a theoretical model. According to this model the effect of the energy threshold decrease results from indirect oblique transitions of the hydrogen atom (with the violation of Frank-Condon approach). This model is of great importance in other photo-stimulated processes in synthetic polymers and biopolymers. For example, it was used for the explanation of hydrogen atom transition probability from the intermediate K610 state to the Br570 state under irradiation with energy lower than 1.97 eV in the process of the bacteriorhodopsin phototransformations in purple diaphragms. This model may also be applied to describe photo-degradation processes in different polymer structures. (C) 2000 Elsevier Science S.A. All rights reserved.