The electronic interactions which promote singlet-singlet and triplet-triplet electronic excitation (energy) transfer (EET) are investigated in detail. Donor and acceptor locally excited configurations, ψ(A*B) and ψ4(AB*), respectively, are each allowed to mix with bridging ionic configurations, ψ2(A+B-) and ψ3(A-B+) to form the new donor and acceptor wave functions ΨR= ψ1+λψ2+μψ3 and ΨP=ψ4+μψ2+λψ 3. Use of the latter wave functions leads to the establishment of the matrix element TRP=〈ΨR|H-E1|Ψ P〉≈=T14-(T12T24+T 13T34)/A, with Tij=〈ψi|H- E1|ψj〉 and A = E2 - E1, as the exciton resonance interaction term for EET. Introduction of the Mulliken approximation shows that the "direct" exciton resonance interaction term (T14) contributes primarily a Coulombic interaction, for singlet-singlet EET, while the "through-configuration" exciton resonance interaction term [-(T12T24+T13T 34)/A] replaces the Dexter exchange integral (which is a component of H14) as the primary source of short-range orbital overlap-dependent EET. The origins of "Dexter-type" energy transfer are thus shown to be quite different from that originally outlined.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry