Femtosecond solvation and charge transfer dynamics in liquid solution

Abstract

Time-resolved fluorescence up-conversion experiments have been performed for a few fluorescent organic charge transfer molecules in liquid solution. Dynamic Stokes shifts have been measured, with a time resolution of 150 fs, for the probe molecules in alcoholic and ethereal solvents. The results reveal solvation dynamics determined by “inertial free streaming” motions of the solvent molecules in the solvent cages and rotational diffusion motions of the solvent molecules. Simulations of the temporal changes in the fluorescence spectra based on the Smoluchowski diffusion equation are also briefly discussed.