Physical-Organic Photochemistry. I. Introduction and σ → σ*, π → π* Excitations
In the limited time and space available for these topics a coherent resume of organic photochemistry in terms of detailed molecular orbital descriptions is inappropriate. Instead what is offered here are selected topics in physical-organic photochemistry which may be of some interest. As a brief introduction, Figure 1 (over) shows some of the important unimolecular physical and chemical decay paths in a complex polyatomic molecule following S0 → S1 excitation. The quantum yield of any process is defined as the rate of that process relative to the rate of light absorption. For steady-state illumination it is easily shown that, for example, the quantum yield of fluorescence for a molecule undergoing the processes shown in Figure l is where rate-constant subscripts refer to the processes shown in Figure 1.
KeywordsQuantum Yield Excited Singlet State Bond Dissociation Energy Vibrational Relaxation Rydberg Transition
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