Time‐resolved resonance Raman study of S 1 cis ‐stilbene and its deuterated isotopomers

We present the picosecond time‐resolved resonance Raman (ps‐TR 3 ) spectra of the first excited singlet state (S 1 ) of cis ‐stilbene ( d 0 ), fully deuterated cis ‐stilbene ( d 12 ) and α,α′‐ d 2 ‐ cis ‐stilbene ( d 2 ) measured in hexane at pump and probe wavelengths 267 and 630 nm, respectively. The main observation is that in the lower wavenumber region the spectra are dominated by a second‐order overtone progression originating from a 229 cm −1 fundamental band for the S 1 d 0 cis ‐stilbene. The observed low‐wavenumber modes of the excited cis ‐stilbene are substantially more resonantly enhanced than the modes around 1600 cm −1 . Copyright © 2003 John Wiley & Sons, Ltd.