Time-dependent density functional theory is thoroughly benchmarked for the predictive calculation of UV–vis spectra of porphyrin derivatives. With the aim to provide an approach that is computationally feasible for large-scale applications such as biological systems or molecular framework materials, albeit performing with high accuracy for the Q-bands, the results given by various computational protocols, including basis sets, density-functionals (including gradient corrected local functionals, hybrids, double hybrids and range-separated functionals), and various variants of time-dependent density functional theory, including the simplified Tamm–Dancoff approximation, are compared. An excellent choice for these calculations is the range-separated functional CAM-B3LYP in combination with the simplified Tamm–Dancoff approximation and a basis set of double-ζ quality def2-SVP (mean absolute error [MAE] of ≈0.05 eV). This is not surpassed by more expensive approaches, not even by double hybrid functionals, and solely systematic excitation energy scaling slightly improves the results (MAE ≈0.04 eV).
Bibliographical noteFunding Information:
This work was supported by the Deutsche Forschungsgemeinschaft (DFG) under the COORNETs Priority Project SPP 1928 (HE 3543/30-1). The computations were performed on a Taurus cluster at the Center of Information Services and ZIH at TU Dresden. T.H. thanks Prof. Carlo Adamo (ParisTech) for fruitful discussions.
All Science Journal Classification (ASJC) codes
- Modelling and Simulation
- Numerical Analysis
- Statistics and Probability