Spectroscopic tracking of structural evolution in ultrafast stilbene photoisomerization.

摘要: Understanding a chemical reaction ultimately requires the knowledge of how each atom in reactants moves during product formation. Such is seldom complete and often limited to an oversimplified coordinate that neglects global motions across molecular framework. To overcome this limit, we recorded transient impulsive Raman spectra ultrafast photoisomerization cis-stilbene solution. The results demonstrate gradual frequency shift low-frequency spectator vibration, reflecting changes restoring force along throughout isomerization. A high-level quantum-chemical calculation reproduces feature associates it with continuous structural change leading twisted configuration. This combined spectroscopic computational approach should be amenable detailed visualization other photoisomerizing systems as well.