Skip to Main content Skip to Navigation
Journal articles

A systematic benchmark of the ab initio Bethe-Salpeter equation approach for low-lying optical excitations of small organic molecules

Abstract : The predictive power of the ab initio Bethe-Salpeter equation (BSE) approach, rigorously based on many-body Green’s function theory but incorporating information from density functional theory, has already been demonstrated for the optical gaps and spectra of solid-state systems. Interest in photoactive hybrid organic/inorganic systems has recently increased and so has the use of the BSE for computing neutral excitations of organic molecules. However, no systematic benchmarks of the BSE for neutral electronic excitations of organic molecules exist. Here, we study the performance of the BSE for the 28 small molecules in Thiel’s widely used time-dependent density functional theory benchmark set . We observe that the BSE produces results that depend critically on the mean-field starting point employed in the perturbative approach. We find that this starting point dependence is mainly introduced through the quasiparticle energies obtained at the intermediate GW step and that with a judicious choice of starting mean-field, singlet excitation energies obtained from BSE are in excellent quantitative agreement with higher-level wavefunction methods. The quality of the triplet excitations is slightly less satisfactory.
Complete list of metadatas

https://hal-cea.archives-ouvertes.fr/cea-02389606
Contributor : Amplexor Amplexor <>
Submitted on : Monday, December 2, 2019 - 3:46:49 PM
Last modification on : Tuesday, April 28, 2020 - 11:28:14 AM

Links full text

Identifiers

Collections

CEA | DEN

Citation

Fabien Bruneval, Samia Hamed, Jeffrey Neaton. A systematic benchmark of the ab initio Bethe-Salpeter equation approach for low-lying optical excitations of small organic molecules. Journal of Chemical Physics, American Institute of Physics, 2015, 142 (24), pp.244101. ⟨10.1063/1.4922489⟩. ⟨cea-02389606⟩

Share

Metrics

Record views

46