Ultrafast dynamics of intra- and intermolecular interactions in liquids and films

Ultrafast Dynamics of Intra- and Inter-molecular Interactions in Liquids and Films Evgeniia Salamatova Intra- and inter-molecular interactions determine many dynamical properties in bio- and energy-related materials such as energy transfer, vibrational relaxation and exciton diffusion. An understanding of such processes is very helpful for predicting more complex properties (e.g. hydrogen bonding and structural organization) as well as for designing new materials. In this thesis, the dynamical properties of liquids and solid films are studied by ultrafast spectroscopy. We show that the molecules with a single peptide bond (-CONH-) form atypical for liquids well-organized structures, which promote intermolecular energy transfer. If such molecules are dissolved in water, the energy migration between molecules is not largely affected but the molecules begin to experience a hydrophobic collapse. Similarly, spectroscopy on diluted alcohols demonstrates that the dynamical properties of the bulk alcohols are determined by intermolecular interactions while the intramolecular ones play a minor role. In contrast, for solid films of organic photovoltaic materials, both intra- and intermolecular interactions are crucial for energy transfer and exciton dynamics. The current thesis forms a convenient basis for predicting dynamical and structural properties of (bio)molecular systems with natural extension to e.g. DNA and proteins. The obtained results are also instrumental for designing new molecules for organic electronics applications.