Photoreactive Disordered Systems Studied by Permanent and Transient Hole-Burning

Abstract

Abstract Permanent and transient hole-burning experiments carried out on various types of amorphous systems at temperatures between 0.3 and 20 K are presented. Optical dephasing on organic molecules in glasses and polymers measured on different time scales are discussed in relation to spectral diffusion processes and compared to the literature. The pure dephasing time appears to be proportional to the excited state lifetime of the guest. Organic molecules adsorbed on the surface of porous silica glass show that their homogeneous linewidth is an order of magnitude larger than in polymers and glasses in the bulk, but follows the same temperature dependence. Hole-burning results on bacteriochlorophyll in various disordered hosts are compared to those on a isolated light-harvesting photosynthetic pigment-protein complex (B800–850). From the holewidth in the latter the energy transfer rate between aggregated bacteriochlorophyll pigments is determined and compared to time-resolved spectroscopy results in the li...