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Title: An assessment of low-lying excitation energies and triplet instabilities of organic molecules with an ab initio Bethe-Salpeter equation approach and the Tamm-Dancoff approximation

Authors:
 [1];  [2];  [3];  [4]
  1. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Department of Physics, University of California, Berkeley, California 94720, USA
  2. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Department of Physics, University of California, Berkeley, California 94720, USA, Department of Chemistry, University of California, Berkeley, California 94720, USA
  3. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Department of Physics, University of California, Berkeley, California 94720, USA, Service de Recherches de Métallurgie Physique, CEA, DEN, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
  4. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Department of Physics, University of California, Berkeley, California 94720, USA, Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1361875
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 146; Journal Issue: 19; Related Information: CHORUS Timestamp: 2018-02-14 21:53:45; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Rangel, Tonatiuh, Hamed, Samia M., Bruneval, Fabien, and Neaton, Jeffrey B. An assessment of low-lying excitation energies and triplet instabilities of organic molecules with an ab initio Bethe-Salpeter equation approach and the Tamm-Dancoff approximation. United States: N. p., 2017. Web. doi:10.1063/1.4983126.
Rangel, Tonatiuh, Hamed, Samia M., Bruneval, Fabien, & Neaton, Jeffrey B. An assessment of low-lying excitation energies and triplet instabilities of organic molecules with an ab initio Bethe-Salpeter equation approach and the Tamm-Dancoff approximation. United States. doi:10.1063/1.4983126.
Rangel, Tonatiuh, Hamed, Samia M., Bruneval, Fabien, and Neaton, Jeffrey B. Sun . "An assessment of low-lying excitation energies and triplet instabilities of organic molecules with an ab initio Bethe-Salpeter equation approach and the Tamm-Dancoff approximation". United States. doi:10.1063/1.4983126.
@article{osti_1361875,
title = {An assessment of low-lying excitation energies and triplet instabilities of organic molecules with an ab initio Bethe-Salpeter equation approach and the Tamm-Dancoff approximation},
author = {Rangel, Tonatiuh and Hamed, Samia M. and Bruneval, Fabien and Neaton, Jeffrey B.},
abstractNote = {},
doi = {10.1063/1.4983126},
journal = {Journal of Chemical Physics},
number = 19,
volume = 146,
place = {United States},
year = {Sun May 21 00:00:00 EDT 2017},
month = {Sun May 21 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4983126

Citation Metrics:
Cited by: 7works
Citation information provided by
Web of Science

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  • Cited by 42
  • 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 setmore » [Schreiber et al., J. Chem. Phys. 128, 134110 (2008)]. 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.« less
  • A systematic ab initio treatment of the nitryl halides (XNO{sub 2}) and the cis- and trans- conformers of the halide nitrites (XONO), where X = Cl, Br, and I, have been carried out using highly correlated methods with sequences of correlation consistent basis sets. Equilibrium geometries and harmonic frequencies have been accurately calculated in all cases at the explicitly correlated CCSD(T)-F12b level of theory, including the effects of core-valence correlation for the former. Where experimental values are available for the equilibrium structures (ClNO{sub 2} and BrNO{sub 2}), the present calculations are in excellent agreement; however, the X-O distances are slightlymore » too long by about 0.01 Å due to missing multireference effects. Accurate predictions for the iodine species are made for the first time. The vertical electronic excitation spectra have been calculated using equation-of-motion coupled cluster methods for the low-lying singlet states and multireference configuration interaction for both singlet and triplet states. The latter also included the effects of spin-orbit coupling to provide oscillator strengths for the ground state singlet to excited triplet transitions. While for ClNO{sub 2} the transitions to excited singlet states all occur at wavelengths shorter than 310 nm, there is one longer wavelength singlet transition in BrNO{sub 2} and two in the case of INO{sub 2}. The long wavelength tail in the XNO{sub 2} species is predicted to be dominated by transitions to triplet states. In addition to red-shifting from X = Cl to I, the triplet transitions also increase in oscillator strength, becoming comparable to many of the singlet transitions in the case of INO{sub 2}. Hence in particular, the latter species should be very photolabile. Similar trends are observed and reported for the halogen nitrites, many of which for the first time.« less
  • Energies from the GW approximation and the Bethe–Salpeter equation (BSE) are benchmarked against the excitation energies of transition-metal (Cu, Zn, Ag, and Cd) single atoms and monoxide anions. We demonstrate that best estimates of GW quasiparticle energies at the complete basis set limit should be obtained via extrapolation or closure relations, while numerically converged GW-BSE eigenvalues can be obtained on a finite basis set. Calculations using real-space wave functions and pseudopotentials are shown to give best-estimate GW energies that agree (up to the extrapolation error) with calculations using all-electron Gaussian basis sets. We benchmark the effects of a vertex approximationmore » (ΓLDA) and the mean-field starting point in GW and the BSE, performing computations using a real-space, transition-space basis and scalar-relativistic pseudopotentials. Here, while no variant of GW improves on perturbative G0W0 at predicting ionization energies, G0W0Γ LDA-BSE computations give excellent agreement with experimental absorption spectra as long as off-diagonal self-energy terms are included. We also present G0W0 quasiparticle energies for the CuO , ZnO , AgO , and CdO anions, in comparison to available anion photoelectron spectra.« less
  • The number conservation as introduced by Lipkin and Nogami has been incorporated in the modified Tamm-Dancoff approximation method. The necessary relevant formulas arising due to this modification are derived and applied to the even Ni isotopes employing the Kuo-Brown effective interaction. A general improvement in agreement with experiments is obtained.