Pulling the Levers of Photophysics: How Structure Controls the Rate of Energy Dissipation

摘要

The process of internal conversion is at the heart of many chemical reactions by being responsible for the conversion of electronic excitation energy into vibrational energy. The ultrafast process from higher electronic states assures that it can rival competing pathways. This also implies that nuclear motion in only a very few vibrational degrees of freedom are involved in internal conversion—if more were to take part the rate of energy dissipation would simply not be able to compete with the rate of photochemical reaction or radiative transition. This is inherently different from thermalized reactions where the total number of degrees of freedom of the system influences the rate of reaction because of the statistical distribution of energy. Such statistical behavior is not necessarily observed by ultrafast, excited-state reac-tions.