Screening of exciplex formation by distant electron transfer

Area of Science:

• Physical Chemistry
• Photochemistry
• Chemical Kinetics

Background:

• Excitation quenching is crucial in photochemistry.
• Exciplex formation and electron transfer are key quenching mechanisms.
• Understanding these processes requires theoretical modeling.

Purpose of the Study:

• To investigate excitation quenching via reversible exciplex formation and distant electron transfer.
• To develop a theoretical model using integral encounter theory (IET).
• To analyze the influence of diffusion and ionization on these quenching pathways.

Main Methods:

• Application of integral encounter theory (IET).
• Derivation of IET equations for excitations, free ions, and exciplexes.
• Solving equations to obtain Laplace images and determine quantum yields.

Main Results:

• Diffusion facilitates exciplex production and electron transfer.
• Stronger electron transfer leads to reduced exciplex production.
• Slow diffusion and high ionization rates cause a screening effect, hindering exciplex formation.

Conclusions:

• Diffusion plays a dual role in excitation quenching dynamics.
• A balance exists between exciplex formation and electron transfer.
• The study provides insights into controlling photochemical reactions through diffusion and ionization rates.