Two-color flash photolysis

The high intensity of the laser beam introduces new reactions, not observed under conditions usual for preparative photochemistry (see Sect 6.2.1), such as triplet-triplet annihilation. Likewise, two photons may be absorbed and ionization may be observed from a higher excited state. However, the increased time resolution makes also possible to manipulate the intermediates. Thus, two-color flash photolysis makes use of a second laser pulse for inducing a reaction of a relatively long lived species, such as radicals and triplets (Scheme 6.6). 

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