Jump to main content
Jump to site search

Issue 22, 2009
Previous Article Next Article

Computation of accurate excitation energies for large organic molecules with double-hybrid density functionals

Author affiliations

Abstract

Time-dependent double-hybrid density functional methods are evaluated for the calculation of vertical singlet–singlet valence excitation energies of a wide variety of organic molecules. Beside the already published TD-B2-PLYP method, an analogous approach based on the recently published ground state B2GP-PLYP functional is presented for the first time. Double-hybrid functionals contain a hybrid-GGA-like part for which a conventional TDDFT linear response treatment is carried out. The thus obtained excitation energies are afterwards corrected by adding a non-local correlation portion, which is based on an CIS(D) type excited state perturbative correction. Both, TD-B2-PLYP and TD-B2GP-PLYP, are first applied to the 142 vertical singlet excitation energies in a benchmark set by Schreiber et al., that contains small and medium sized organic molecules. In a second part, a new benchmark set composed of five large organic dyes is proposed. Accurate reference values are derived from experimental 0–0 excitation energies in solution. A back-correction scheme based on TDDFT computations is presented by which solvent, relaxation and vibrational effects are removed, yielding experimental vertical gas phase excitation energies with an estimated accuracy of about ±0.1 eV. The TD-B2-PLYP, TD-B2GP-PLYP and a variety of conventional TDDFT methods are then applied to this new benchmark set. The results for both considered test sets show that the new double-hybrid approaches yield the smallest mean absolute deviations of 0.22 eV for the first benchmark set and 0.19 eV (TD-B2-PLYP) and 0.16 eV (TD-B2GP-PLYP) for the new organic dye test set. Apart from a break-down of the perturbative correction for very high-lying transitions (larger than 8 eV), it is generally found that the double-hybrid functionals show high robustness and accuracy that cannot be obtained with conventional density functionals (e.g. B3-LYP).

Graphical abstract: Computation of accurate excitation energies for large organic molecules with double-hybrid density functionals

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Feb 2009, accepted on 02 Mar 2009 and first published on 23 Mar 2009


Article type: Paper
DOI: 10.1039/B902315A
Citation: Phys. Chem. Chem. Phys., 2009,11, 4611-4620
  •   Request permissions

    Computation of accurate excitation energies for large organic molecules with double-hybrid density functionals

    L. Goerigk, J. Moellmann and S. Grimme, Phys. Chem. Chem. Phys., 2009, 11, 4611
    DOI: 10.1039/B902315A

Search articles by author

Spotlight

Advertisements