The anti-Stokes resonance Raman spectrum of photoexcited S1 trans-stilbene

Anti-Stokes resonance Raman spectra of S1 trans-stilbene have been measured for vibrational wavenumbers up to 1570 cm−1. Trans-stilbene in n-hexane was excited at 290–310 nm and probed at 580–620 nm, respectively, with 8 ps resolution. All the dominant bands seen in the Stokes spectrum of the S1 state are also seen in the anti-Stokes spectrum. Some anti-Stokes bands, notably those at 1570, 1240, 1180, 980, 720 and 285 cm−1, decrease markedly in relative intensity on a 2~ 10 ps timescale, displaying dynamics similar to those observed for the changes in the band position and bandwidth of several features in the Stokes spectrum.