Deactivation processes, transient electronic states

Excited states may be quenched as well via an electron transfer between the excited and quencher molecular entities. The electron can be transferred by two alternative ways, generating a radical anion and cation as a transient species (Figure 4.4). These then react thermally when the reaction leads to reproduction substrate AB and quencher Q in their ground states, the photophysical deactivation occurs when radical ions react with other medium components generating new species, the process belongs to photochemical redox reactions (see Chapter 6). 

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