Intramolecular Charge Transfer Probed by Femtosecond Stimulated Raman Spectroscopy

Abstract

The intramolecular charge transfer of a fluorescent dye DCM has been explored by femtosecond stimulated Raman spectroscopy with both high temporal (<50 fs) and spectral resolutions (<10 cm 1 ). Distinct vibrational spectra of the locally-excited and charge-transferred conformers of DCM in the excited state were observed in DMSO and chloroform solutions. We propose that a twisted molecular geometry in the electron donating group (dimethylamino or dimethylaminophenyl) would be favored in the intramolecular charge transfer state of DCM.