Femtosecond Excited State Dynamics From Resonance Raman Intensities

The quannitative analysis of resonance Raman excitation profiles provides a vehicle for understanding the femtosecond excited state dynamics of molecules. The sum-over-states and time-dependent wave packet methods for analyzing resonance Raman intensities are presented. The practical and conceptual advantages of the time-dependent approach are discussed. The resonance Raman excitation profiles and absorption spectrm of cis -stilbene are analyzed to illustrate the time-dependent method. An explicit picture of the short time (20 femtosecond) dynamics that lead to excited state cis → trans isomerization of stilbene is presented.