"The use of chromophore rotational motion to study local organization is well established. Under certain conditions, the same measurements can be used to evaluate the effect(s) of thermal energy transfer from the chromophore to the bath. Such information is of central importance to gaining a fundamental understanding of the intermolecular interactions that are ultimately responsible for bulk system properties, and to the creation of biomimetic mono- and bilayer structures. This thesis includes studies that address each of these areas. The first study, focusing on understanding the molecular scale consequences of thermal energy dissipation in bulk systems, reports on the rotational diffusion dynamics of tetracene in a series of n-alkane solvents, where differences in those dynamics were measured for excitation to the S1 and S2 states. These data demonstrated that for excitation to the S2 state, fast nonradiative relaxation to the S1 state produces transient heating of the solvent surrounding the chromophore, with the details depending on the identity of the solvent bath. The second study aims at understanding the influence of the aqueous overlayer in contact with a planar bilayer on molecular scale organization and phase separation. These data reveal organization-dependent changes in the bilayer that depend on both the pH and the ionic strength of the aqueous overlayer. These findings are of direct relevance to the use of such films in the construction of biomimetic sensors, for example, where organization is expected to influence the ability of the bilayer to host biomolecules in their active forms and to mediate permeability."--Page ii.
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