The structure of electronic excited states in t r a n s-stilbene: Picosecond transient Stokes and anti-Stokes Raman spectra

We measured picosecond transient Stokes and anti-Stokes Raman spectra of S1 trans-stilbene in hexane. We observed 18 vibrational modes in the Stokes spectra and two modes in the low wave number anti-Stokes spectra. The band positions and band shapes of the transient Raman spectra suggest a distribution of molecular conformers in S1 having different single and double bond strengths. The band intensities suggest a redistribution of electron density in Sn that is concentrated in the olefinic region and in the ortho and meta region of the phenyl rings.