Liu W, Settels V, Harbach PHP, Dreuw A, Fink RF, Engels B. Assessment of TD-DFT- and TD-HF-based approaches for the prediction of exciton coupling parameters, potential energy curves, and electronic characters of electronically excited aggregates.
J Comput Chem 2011;
32:1971-81. [PMID:
21484836 DOI:
10.1002/jcc.21781]
[Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 01/18/2011] [Accepted: 02/02/2011] [Indexed: 11/08/2022]
Abstract
The reliability of linear response approaches such as time-dependent Hartree-Fock (TD-HF) and time-dependent density functional theory (TD-DFT) for the prediction of the excited state properties of 3,4;9,10-tetracarboxylic-perylene-bisimide (PBI) aggregates is investigated. A dimer model of PBI is investigated as a function of a torsional motion of the monomers, which was shown before to be an important intermolecular coordinate in these aggregates. The potential energy curves of the ground state and the two energetically lowest neutral excited and charge-transfer (CT) states were obtained with the spin-component scaling modification of the approximate coupled-cluster singles-and-doubles (SCS-CC2) method as a benchmark for dispersion corrected TD-HF and a range of TD-DFT approaches. The highly accurate SCS-CC2 results are used to assess the other, computationally less demanding methods. TD-HF predicts similar potential energy curves and transition dipole moments as SCS-CC2, as well as the correct order of neutral and CT states. This supports an exciton trapping mechanism, which was found on the basis of TD-HF data. However, the investigated TD-DFT methods provide generally the opposite character for the excited states. As a consequence, these TD-DFT results have unacceptably large errors for optical properties of these dye aggregates.
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