Time-resolved fluorescence spectra of cis-stilbene in hexane and acetonitrile

Transient fluorescence spectra from cis-stilbene in solution are recorded with 0.24 ps instrument response by a Kerr–Shutter upon excitation at 283 and 267 nm. The fluorescence decay shows no dependence on the excitation wavelength and proceeds monoexponentially with 0.21 ps in acetonitrile and 0.75 ps in hexane. No spectral shift or distortion of the fluorescence band is observed during the decay. Fluorescence contribution from 4a,4b-dihydrophenanthrene (DHP), produced in a competing reaction channel, was not detectable. From comparison with trans-fluorescence, the emission oscillator strength of cis-stilbene is determined to be 0.19 in hexane and 0.21 in acetonitrile.