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The goal is to use the advantages of modern computational facilities for studying the relaxation and energy transfer processes of molecules and impurity centres embedded in a condensed matrix, taking into account detailed microscopic structures and interactions of solids and molecular systems. The main topic is the evolution of the coherence of excitations as an essential feature of nonlinear interactions in matter. To study vibrational relaxation processes via the time-resolved nonlinear technique like coherent anti-Stokes Raman scattering (CARS), the developing of the theory for the third-order polarization of multimode vibronic systems is planned, taking into account mode mixing which plays a crucial role in phase relaxation. In connection with new experimental methods in ?-spectroscopy, theoretical models which more precisely describe the coupling of resonant nuclei with their surroundings will be introduced, taking into account low-frequency pseudolocal modes of Fe-ions, diffusion-type motions. Important from the viewpoint of modern technology rare gas crystals, where most relaxation processes involve diatomic excimer centres or their crystal analogues, self-trapped excitons, will also be examined. For that the software for spectral calculations of diatomic species, which bases on the Franck-Condon principle, will essentially be improved. It is planned to combine the new Franck-Condon methods with photoassociative spectroscopic studies. The investigation of the radiationless energy transfer processes between donor-acceptor pairs in molecular systems with spatial restrictions, like zeolites, polymer mixtures, porous materials, is planned.
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