Is ADC(3) as Accurate as CC3 for Valence and Rydberg Transition Energies?

Abstract

The search for new models rapidly delivering accurate excited-state energies and properties is one of the most active research lines of theoretical chemistry. Along with these developments, the performance of known methods is constantly reassessed on the basis of new benchmark values. In this Letter, we show that the third-order algebraic diagrammatic construction, ADC(3), does not yield transition energies of the same quality as the third-order coupled cluster method, CC3. This is demonstrated by extensive comparisons with several hundred high-quality vertical transition energies obtained with FCI, CCSDTQ, and CCSDT. Direct comparisons with experimental 0–0 energies of small- and medium-size molecules support the same conclusion, which holds for both valence and Rydberg transitions. Considering these results, we introduce a composite approach, ADC(2.5), which consists of averaging the ADC(2) and ADC(3) excitation energies. Although ADC(2.5) does not match the CC3 accuracy, it significantly improves the ADC(3) results, especially for vertical energies.

Triangular boron carbon nitrides: an unexplored family of chromophores with unique properties for photocatalysis and optoelectronics

“…58 The accuracy of CC2 and ADC(2) for excitation energies of organic molecules was extensively benchmarked in comparison with more accurate methods, such as CC3 and CCSDT. [59][60][61][62] A mean absolute error of ≈ 0. 22 eV for low-lying singlet states and ≈ 0.12 eV for low-lying triplet states has been estimated.…”

Dynamical Correction to the Bethe-Salpeter Equation Beyond the Plasmon-Pole Approximation

“…These will be our reference as they are known to be extremely accurate (0.03-0.04 eV from the TBEs). [30][31][32]83 Errors associated with these excitation energies (with respect to CC3) are represented in Fig. 2.…”

“…46 and 47, we consider here as reference high-level CC calculations performed with the very same geometries and basis sets than our BSE calculations. As pointed out in previous works, [83][84][85] a direct comparison between theoretical transition energies and experimental data is a delicate task, as many factors (such as zero-point vibrational energies and geometrical relaxation) must be taken into account for fair comparisons. Further investigations are required to better evaluate the impact of these considerations on the influence of dynamical screening.…”

Weight Dependence of Local Exchange-Correlation Functionals in Ensemble Density-Functional Theory: Double Excitations in Two-Electron Systems

“…Time-dependent density-functional theory (TD-DFT) has been the dominant force in the calculation of excitation energies of molecular systems in the last two decades. [1][2][3] At a moderate computational cost (at least compared to the other excited-state ab initio methods), TD-DFT can provide accurate transition energies for low-lying excited states of organic molecules (see, for example, Ref. 4 and references therein).…”