Title Aplinkos poveikis fotoindukuotiems reiškiniams organinėse molekulėse /
Translation of Title Environmental effects on photoinduced processes in organic molecules.
Authors Mačernis, Mindaugas
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Pages 136
Keywords [eng] Schiff base ; proton transfer ; potential energy surfaces ; carotenoids ; molecular mechanics and quantum-chemical calculations
Abstract [eng] To explore changes caused by the environment on the internal characteristics of an organic molecule is the objective of the thesis. For this purpose we investigate a variety of organic molecules. Using various methods of quantum mechanics calculations possible influence of a polar solvent on the ground and excited states of 2-(N-metil-α-iminoethyl)-fenol and N-triphenylmethylsalicylidene imine is considered. It is shown for the first time that in order to obtain the correct qualitative and quantitative interpretation of possible pathways of the intermolecular proton transfer the hydrogen network of the polar solvent molecules together with the zero point energy have to be taken into consideration. It is also shown that conformational variability of anil-type molecules in polar solvents is competing with clusters formation of solvent molecules. It is shown for the first time that the dipole moment of bacteriorhodopsin is mainly defined by cytoplasmic and extracellular coils on the surfaces of the membrane. It is also demonstrated that the stilbazole molecule experiences the deformation resulting in formation of new conformers (at least two forms are present) in the solvent surrounding. The experimental data of the transient spectroscopy were explained in the basis of these model calculations. The lowest excited states of carotinoids, such as lutein, zeaxanthin and violoxantin are calculated and analyzed. Sensitivity of the excited electronic state on the polar environment is demonstrated. The results of the thesis demonstrate the possible influence of the polar environment on the photoinduced processes in organic molecules. Namely, the proton transfer and formation of conformers in the polar environment are understood in terms of these results. The origin of the driving force for the proton transfer in bacteriorhodopsin and observations of the spectral changes in the photosynthetic light-harvesting complexes at high light conditions are also understood. Various experimental observations are explained on the basis of these results what evidently is of the practical importance.
Type Doctoral thesis
Language Lithuanian
Publication date 2011