Picosecond real-time studies of mode-specific vibrational predissociation

The vibrational predissociation of several van der Waals complexes of t-stilbene has been studied by directly measuring, in real time, the fluorescence intensity from the initial reactant state and from the individual product states formed in the dissociation process after exciting single vibrational levels of the complex. With the aid of a kinetic model involving sequential processes, the individual rates for intramolecular vibrational redistribution and vibrational predissociation in the overall dissociation process are resolved and distinguished in several cases. In the stilbene–He complex, the dissociation is significantly faster from low energy out-of-plane modes than it is from a higher energy in-plane mode