FREQUENCY-DEPENDENCE OF SPECTRAL DIFFUSION IN HOLE-BURNING SYSTEMS - RESONANT EFFECTS OF INFRARED RADIATION

Light-induced spectral diffusion in photochemical hole-burning systems is investigated with respect to its dependence on the frequency of the irradiated light in the wavelength range between 2 and 5-mu-m. The investigated systems are protonated and deuterated polymethyl methacrylate (PMMA) matrices doped with metal-free phthalocyanine (H2Pc). Resonant hole-filling and resonant hole-broadening behaviors are found, both being caused by the excitation of local, but different, matrix vibrations, Possible mechanisms are discussed under the aspect of the excitation of IR- and Raman-active vibrations of the matrix.