Harrer E, Müller C, Zahn D (2026)
Publication Type: Journal article
Publication year: 2026
Original Authors: Elias Harrer, Carolin Müller, Dirk Zahn
Book Volume: 47
Article Number: e70495
Issue: 24
Journal Issue: 24
DOI: 10.1002/jcc.70495
The accurate prediction of electronically excited states is essential for the computational design of molecular photoswitches but remains challenging for thioindigoid chromophores owing to their complex excited-state electronic structure. In this work, we establish theoretical best estimates for the two lowest singlet and three lowest triplet vertical excitation energies of a chemically diverse set of hemithiophenindigo (HTPI) derivatives using high-level coupled cluster methods (CC3 and CCSDT). The selected model systems retain the characteristic chromophoric core of thioindigo and hemithioindigo photoswitches while remaining accessible to benchmark calculations. Analysis of electron-rich and electron-poor derivatives reveals pronounced position-dependent effects on the low-lying excited states that closely resemble trends reported for larger thioindigoid chromophores. Based on this reference data, we benchmark 65 semiempirical and quantum-chemical methods, including density functional approximations across multiple rungs of Jacob's ladder as well as single- and multireference wave function approaches. To identify computationally efficient workflows for future virtual screening studies, we additionally assess 25 combinations of ground state geometry optimization and excitation-energy methods. The resulting recommendations for singlet-singlet and singlet-triplet excitation energies provide a validated methodological foundation for large-scale in silico exploration of thioindigo and hemithioindigo dyes, thus enabling the screening of tens of thousands of candidate chromophores while retaining high overall accuracy.
APA:
Harrer, E., Müller, C., & Zahn, D. (2026). Benchmark Reference Data and Computational Protocols for Predicting Excitation Energies of Thioindigoid Photoswitches. Journal of Computational Chemistry, 47(24). https://doi.org/10.1002/jcc.70495
MLA:
Harrer, Elias, Carolin Müller, and Dirk Zahn. "Benchmark Reference Data and Computational Protocols for Predicting Excitation Energies of Thioindigoid Photoswitches." Journal of Computational Chemistry 47.24 (2026).
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