Chirped molecular vibration in a stilbene derivative in solution

The wave packet dynamics of 4-methoxy-4′-nitrostilbene in solution was studied by femtosecond pump-probe spectroscopy. Transient changes in absorbance exhibit oscillations, which reflect vibrational motions on the ground-state potential surface. Modification of this oscillatory feature in three different solvents (benzene, methanol, and acetonitrile) can be explained in term of the strength of hydrogen bonding and the stabilization of charge-transfer state, confirmed by steady-state absorption and fluorescence spectra.