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Updated: Apr 28, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Modeling Triplet Excited-State Energy Transfer (TEET) via Multistate Density Functional Theory with Nonorthogonal
Jiali Gao1,2,3, Kai Chen1, Chenyu Liu1
1Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota55455, United States.
Abstract:
We present a computational protocol for triplet excited-state energy transfer (TEET) within multistate density functional theory with nonorthogonal state interaction (MSDFT-NOSI). Block-localized excitation, achieved through occupation-constrained orbital optimization, generates fragment-localized singlet and triplet configurations in a minimal active space that captures donor and acceptor states. Well-defined diabatic states, with excitations localized on individual fragments, are obtained via the generalized diabatic-at-construction (GDAC) transformation. This yields diabatic energies and electronic couplings for both Dexter-type and Förster-type transfer in a unified framework. Application to the propenal excimer demonstrates that MSDFT-NOSI reproduces TDDFT-quality excitation energies while providing a chemically transparent picture of the TEET process. MSDFT-NOSI/GDAC offers a practical and insightful method for investigating triplet energy transfer in molecular complexes and photocatalytic systems.
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