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Title: Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations

Abstract

We introduce a database (HAB11) of electronic coupling matrix elements (H{sub ab}) for electron transfer in 11 π-conjugated organic homo-dimer cations. High-level ab inito calculations at the multireference configuration interaction MRCI+Q level of theory, n-electron valence state perturbation theory NEVPT2, and (spin-component scaled) approximate coupled cluster model (SCS)-CC2 are reported for this database to assess the performance of three DFT methods of decreasing computational cost, including constrained density functional theory (CDFT), fragment-orbital DFT (FODFT), and self-consistent charge density functional tight-binding (FODFTB). We find that the CDFT approach in combination with a modified PBE functional containing 50% Hartree-Fock exchange gives best results for absolute H{sub ab} values (mean relative unsigned error = 5.3%) and exponential distance decay constants β (4.3%). CDFT in combination with pure PBE overestimates couplings by 38.7% due to a too diffuse excess charge distribution, whereas the economic FODFT and highly cost-effective FODFTB methods underestimate couplings by 37.6% and 42.4%, respectively, due to neglect of interaction between donor and acceptor. The errors are systematic, however, and can be significantly reduced by applying a uniform scaling factor for each method. Applications to dimers outside the database, specifically rotated thiophene dimers and larger acenes up to pentacene, suggests that themore » same scaling procedure significantly improves the FODFT and FODFTB results for larger π-conjugated systems relevant to organic semiconductors and DNA.« less

Authors:
;  [1];  [1];  [2]; ;  [3];  [4]
  1. Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
  2. (Germany)
  3. Institute of Physical Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany)
  4. Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching (Germany)
Publication Date:
OSTI Identifier:
22253447
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 140; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CATIONS; CHARGE DENSITY; CHARGE DISTRIBUTION; CLUSTER MODEL; COUPLINGS; DENSITY FUNCTIONAL METHOD; DIMERS; DNA; ELECTRON TRANSFER; HARTREE-FOCK METHOD; INTERACTIONS; MATRIX ELEMENTS; ORGANIC SEMICONDUCTORS; PENTACENE; PERTURBATION THEORY; POLYCYCLIC SULFUR HETEROCYCLES; SCALING; THIOPHENE

Citation Formats

Kubas, Adam, Blumberger, Jochen, E-mail: j.blumberger@ucl.ac.uk, Hoffmann, Felix, Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Heck, Alexander, Elstner, Marcus, and Oberhofer, Harald. Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations. United States: N. p., 2014. Web. doi:10.1063/1.4867077.
Kubas, Adam, Blumberger, Jochen, E-mail: j.blumberger@ucl.ac.uk, Hoffmann, Felix, Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Heck, Alexander, Elstner, Marcus, & Oberhofer, Harald. Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations. United States. doi:10.1063/1.4867077.
Kubas, Adam, Blumberger, Jochen, E-mail: j.blumberger@ucl.ac.uk, Hoffmann, Felix, Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Heck, Alexander, Elstner, Marcus, and Oberhofer, Harald. Fri . "Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations". United States. doi:10.1063/1.4867077.
@article{osti_22253447,
title = {Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations},
author = {Kubas, Adam and Blumberger, Jochen, E-mail: j.blumberger@ucl.ac.uk and Hoffmann, Felix and Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum and Heck, Alexander and Elstner, Marcus and Oberhofer, Harald},
abstractNote = {We introduce a database (HAB11) of electronic coupling matrix elements (H{sub ab}) for electron transfer in 11 π-conjugated organic homo-dimer cations. High-level ab inito calculations at the multireference configuration interaction MRCI+Q level of theory, n-electron valence state perturbation theory NEVPT2, and (spin-component scaled) approximate coupled cluster model (SCS)-CC2 are reported for this database to assess the performance of three DFT methods of decreasing computational cost, including constrained density functional theory (CDFT), fragment-orbital DFT (FODFT), and self-consistent charge density functional tight-binding (FODFTB). We find that the CDFT approach in combination with a modified PBE functional containing 50% Hartree-Fock exchange gives best results for absolute H{sub ab} values (mean relative unsigned error = 5.3%) and exponential distance decay constants β (4.3%). CDFT in combination with pure PBE overestimates couplings by 38.7% due to a too diffuse excess charge distribution, whereas the economic FODFT and highly cost-effective FODFTB methods underestimate couplings by 37.6% and 42.4%, respectively, due to neglect of interaction between donor and acceptor. The errors are systematic, however, and can be significantly reduced by applying a uniform scaling factor for each method. Applications to dimers outside the database, specifically rotated thiophene dimers and larger acenes up to pentacene, suggests that the same scaling procedure significantly improves the FODFT and FODFTB results for larger π-conjugated systems relevant to organic semiconductors and DNA.},
doi = {10.1063/1.4867077},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 10,
volume = 140,
place = {United States},
year = {2014},
month = {3}
}