Data-driven approach for benchmarking DFTB-approximate excited state methods

Abstract

In this work we propose a chemically-informed data-driven approach to benchmark the approximate density-functional tight-binding (DFTB) excited state (ES) methods that are currently available within the DFTB+ suite. By taking...

Excited state properties of an A–D–A non-fullerene electron acceptor: a LC-TD-DFTB study

“…These results are consistent when compared to the data-driven benchmark performed by Bertoni and Sanchez. 27 Despite employing a different xc functional with an o-optimization step, we obtained S 1 energy differences between the DFT-based methods smaller than 0.5 eV, as expected for most p-conjugated molecules. For the brightest state, the agreement between the TD-DFT and ADC2 energies is remarkable (5.85 eV and 5.89 eV, respectively), while a higher value was obtained with TD-DFTB (6.00 eV).…”

“…[22][23][24][25] When appropriately tuned, this methodology can significantly improve the accuracy of both orbital energies and the description of charged molecules. 26 Despite the limitations in characterizing the first excited state of unsaturated molecules, 27 LC-TD-DFTB has successfully reproduced long-range corrected time-dependent density functional theory (LC-TD-DFT) results 28 and experimental data involving CT excitations 29 of small organic molecules. In the context of OSCs, the semi-empirical method was employed to study the effect of different donor:acceptor (D:A) architectures on charge transfer 30 and even made it computationally accessible to perform non-adiabatic dynamics for molecules of this size.…”