The effect of hydrogen-bond in alcoholic solvent on the solvation ultrafast dynamics of oxazine 750 dye

The ultrafast dynamics of oxazine 750 dye was studied in methanol, ethanol, 1-propanol, 1-butanol solvents using the femtosecond time-resolved stimulated emission pumping fluorescence depletion (FS TR SEP FD) technique. The faster decays on the hundreds of femtosecond time scale and the slower decays on the order of picosecond were found. The intramolecular vibrational redistribution (IVR) and the solute-solvent intermolecular photoinduced electron transfer (ET) should account for the faster decay, while the slower decay is attributable to the diffusive solvent relaxation. The results show that the intermolecular hydrogen-bonding network will hinder the rearrangement of the alcoholic molecules in the solvation process and the time constants of the slower diffusive solvent relaxation decays are found to increase with the hydrogen-bonding energy in alcoholic solvents