Berlin 2001 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 17: Poster: Spectroscopy and Single Particle Spectroscopy of Molecular Systems, Photoprocesses, Biological Systems

CPP 17.6: Poster

Dienstag, 3. April 2001, 12:30–15:00, AT1

Solute-Solvent Hydrogen Bonding in Binary Solvent Mixtures — •D. Starukhin, F. Cichos, and C. von Borczyskowski — Institut für Physik 122501, TU Chemnitz, 09107 Chemnitz

The solvation of organic molecules is influenced by different types of interactions. One type is for instance an hydrogen bonding interaction. Hydrogen bonds between solute and solvent molecules can become quite important in dilute solutions of a protic solvent in an aprotic environment where the hydrogen bond can significantly stabilize the solvation shell.

We present steady state and time resolved spectroscopic studies on solute-solvent hydrogen bonding in binary solvent mixtures of polar and non-polar molecules. We use the effect of preferential solvation in binary mixtures to create a solvation shell of a few molecules of one solvent component around organic dyes. The experimental studies with different polar protic and polar aprotic solvent components show that the solvation of shell of several Coumarin dyes in a solvent mixture is stabilized by hydrogen bonds and not by dipole or electrostatic interactions. By using red edge excitation we select a sub-ensemble of Coumarin molecules which are solvated by the polar protic solvent component and detect the dynamics of this solvation shell.