Chemical Reaction Dynamics Probed by Time-Resolved Vibrational Spectroscopy |
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ÀϽà : 2019.11.20 17:00 |
¼Ò¼Ó : GIST ÈÇаú |
¹ßÇ¥ÀÚ : ¹æÀ±¼ö |
Àå¼Ò : R404 |
Ultrafast
photophysical processes in the excited states including intramolecular proton
transfers and charge transfers are of fundamental importance in understanding
chemical reactions and many applications. In this work, ultrafast intramolecular
proton transfer of 1,2-dihydroxyanthraquinone (alizarin) and intramolecular
charge transfer of DCM dye and 1-aminoanthraquinone (AAQ) were visualized femtosecond
stimulated Raman spectroscopy. From population and spectral changes of
transient vibrational modes of the probe, structural changes of probe
accompanying proton transfer or charge transfer can be obtained.
Tautomerization of alizarin and twisted intramolecular charge transfer of DCM
dye and AAQ will be discussed. We have also investigated the changes in the
solvent vibrational modes of solvent DMSO during these ultrafast processes. The
n(S=O) and n(CSC) mode substantially
increase especially in the sub-bands for ¡°aggregated¡± species of DMSO while a substantial
decrease in the n(S=O) mode especially in the sub-bands for
¡°hydrogen-bonded¡± species of DMSO was found during the intramolecular charge
transfer of AAQ. In conclusion, we propose that the solvent vibrations of DMSO
can be used as the measure of the chemical reaction dynamics of solute
molecules and solvation dynamics accompanying the ultrafast photophysical
processes. |