Correlation between fluorescence and structure

As mentioned in Section 1.3.2 the chemical constitution of an organic molecule determines whether it fluoresces or not [88,89,90]. In the vapour phase and in solvents, intra-molecular quenching effects determine whether emission will take place in addition to radiationless transitions. Furthermore in solvents the interaction with non-excited molecules (mostly solvent molecules) can cause an intermolecular deactivation process, which also reduces the probability of fluorescence. In principle, high fluorescence yield can be expected, if 

The following effects can cause a reduction of the fluorescence yield by intermolecular deactivation  

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