Déformation photoinduite dans les films minces contenant des ...

Chapter 1. The azobenzene molecules: photochromic materials and photodeformationeffects 9pastel-00527388, version 1 - 19 Oct 2010Figure 1.2: Azobenzene molecule: energy levels Jablonski diagram, supposing tripletstates. The de-excitation probabilities reported have been proposed by Lemarie et al.[27].rotationinversionFigure 1.3: Azobenzene photoisomerization: rotation and inversion mechanisms.The relaxation (de-excitation) may occur through different pathways involving severalintermediate states and corresponding transition probabilities and leads either to therelaxation towards the initial state or to the transition in to the isomer state.mechanism governing the interconversion between the two forms has long been studiedduring the second half of the last century, and is still matter of debate. The two mostaccredited hypothesis are depicted in Figure 1.3. In one case (top), the isomerizationis accomplished through the rotation of a phenyl ring around the -N=N- group, whilein the other case it is obtained via an inversion of a phenyl ring in the plane of themolecule [28].The