Femtosecond polarization resolved spectroscopy: A tool for determination of the three-dimensional orientation of electronic transition dipole moments and identification of configurational isomers

Moritz Theisen, Martin Linke, Max Kerbs, Henk Fidder, Mohamed El Amine Madjet, Angelica Zacarias, Karsten Heyne

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A method is presented that combines femtosecond polarization resolved UV/visible pump-IR probe spectroscopy and density functional theory calculations in determining the three-dimensional orientation of an electronic transition dipole moment (tdm) within the molecular structure. The method is demonstrated on the approximately planar molecule coumarin 314 (C314) dissolved in acetonitrile, which can exist in two ground state configurations: the E - and the Z -isomer. Based on an exhaustive search analysis on polarization resolved measurement data for four different vibrational modes, it is concluded that C314 in acetonitrile is the E -isomer. The electronic tdm vector for the electronic S0 → S1 transition is determined and the analysis shows that performing the procedure for four vibrational modes instead of the minimally required three reduces the 1σ probability area from 2.34% to 2.24% of the solution space. Moreover, the fastest rotational correlation time τc for the C314 E -isomer is determined to be 26±2 ps.

Original languageEnglish
Article number124511
JournalJournal of Chemical Physics
Issue number12
Publication statusPublished - 8 Oct 2009


ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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