Abstract
Time-resolved coherent antistokes Raman spectroscopy (CARS) spectra from an excited singlet state of diphenylhexatriene (DPH) are reported. As determined from the CARS measurements, the excited-state population increases on a sub-picosecond time scale after excitation in the 1Ag-1Bu absorption band. We observe two strongly upshifted and anomalously broadened resonances in the double-bond stretching region. According to our semi-empirical calculations of vibrational frequencies, they can be assigned to polyenic p-chain modes of the 1Bu and 2Ag states, respectively. Frequency shifts as well as broadenings are extremely solvent-dependent, indicating a strong influence on the excited-state conformations. Our time-resolved measurements support a mixed excited singlet state with drastically different geometries of the local minima.
Original language | English (US) |
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Pages (from-to) | 8-16 |
Number of pages | 9 |
Journal | Chemical Physics Letters |
Volume | 287 |
Issue number | 1-2 |
State | Published - Apr 24 1998 |
Externally published | Yes |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Spectroscopy
- Atomic and Molecular Physics, and Optics