Quenching by foreign substances

Physical quenching by foreign added substances generally occur by two broad based mechanisms  

1 Charge Transfer Mechanism Exciplex Formation and Decay 

Molecules with heavy atoms act as quenchers by an exciplex mechanism. 

Jolvation is an important factor affecting such reactions. In some systems Hcognizably free solvated ions may be detected, as when deoxygenated 

4 The solvent-shared ion-pair character of the exciplex increases with the increase in solvent dielectric Constant and ionization potential of the ionor and electron affinity of the acceptor. 

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