Evaluating the Performance of DFT Functionals in Assessing the Interaction Energy and Ground-State Charge Transfer of Donor/Acceptor Complexes: Tetrathiafulvalene−Tetracyanoquinodimethane (TTF−TCNQ) as a Model Case

• Published in: Journal of chemical theory and computation Vol. 7; no. 3; pp. 602 - 609
• Main Authors: Sini, Gjergji, Sears, John S, Brédas, Jean-Luc
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08.03.2011
• Subjects: Quantum Electronic Structure
• ISSN: 1549-9618; 1549-9626
• DOI: 10.1021/ct1005517

We have evaluated the performance of several density functional theory (DFT) functionals for the description of the ground-state electronic structure and charge transfer in donor/acceptor complexes. The tetrathiafulvalene−tetracyanoquinodimethane (TTF−TCNQ) complex has been considered as a model test case. Hybrid functionals have been chosen together with recently proposed long-range corrected functionals (ωB97X, ωB97X-D, LRC-ωPBEh, and LC-ωPBE) in order to assess the sensitivity of the results to the treatment and magnitude of exact exchange. The results show an approximately linear dependence of the ground-state charge transfer with the HOMOTTF−LUMOTCNQ energy gap, which in turn depends linearly on the percentage of exact exchange in the functional. The reliability of ground-state charge transfer values calculated in the framework of a monodeterminantal DFT approach was also examined.