Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 12: Posters Friday: Spectroscopy

MO 12.26: Poster

Freitag, 6. April 2001, 12:30–15:00, AT3

Intramolecular charge transfer of microsolvated DMABN-derivatives studied by infrared depletion spectroscopy observed in the dispersed fluorescence — •Oliver Krauß and Bernhard Brutschy — Institut für Physikalische und Theoretische Chemie, Johann Wolfgang Goethe-Universität, Marie-Curie-Str. 11, D-60439 Frankfurt am Main

The photoinduced intramolecular charge transfer (CT) in 4-N,N-dimethylaminobenzonitrile (DMABN) and related compounds dissolved in polar solvents leads to an additional red-shifted CT fluorescence band (dual fluorescence phenomenon). Under supersonic jet conditions a minimum of five solvent molecules must be attached to the DMABN monomer to induce the formation of the CT state [1]. In contrast to that, methyl 4-N,N-aminobenzoate (DMABME) undergoes the CT reaction when complexed with two water molecules [2].

The presented predissociative vibrational spectroscopy allows one to characterize the size and structure of the relevant solute-solvent clusters. While the red-shifted CT emission shows no significant dependence on the excitation wavelength, the infrared depletion of this band yields specific fingerprints of the complex undergoing CT upon electronic excitation.

[1] O. Krauß et al., Phys. Chem. Chem. Phys., 3, 74, (2001)

[2] C. Dedonder-Lardeux et al., Chem. Phys., 191, 271, (1995)