title: Ultrafast Estimation of Electronic Couplings for Electron Transfer between π-Conjugated Organic Molecules.
abstract: Simulation of charge transport in organic semiconducting materials requires the development of strategies for very fast yet accurate estimation of electronic coupling matrix elements for electron transfer between organic molecules (transfer integrals, Hab). A well-known relation that is often exploited for this purpose is the approximately linear dependence of electronic coupling with respect to the overlap of the corresponding diabatic state wave functions for a given donor-acceptor pair. Here we show that a single such relation can be established for a large number of different π-conjugated organic molecules. In our computational scheme the overlap of the diabatic state wave function is simply estimated by the overlap of the highest singly occupied molecular orbital of donor and acceptor, projected on a minimum valence shell Slater-type orbital (STO) basis with optimized Slater decay coefficients. After calibration of the linear relation, the average error in Hab as obtained from the STO orbital overlap is a factor of 1.9 with respect to wave function-theory validated DFT calculations for a diverse set of π-conjugated organic dimers including small arenes, arenes with S, N, and O heteroatoms, acenes, porphins, and buckyballs. The crucial advantage of the scheme is that the STO orbital overlap calculation is analytic. This leads to speedups of 6 orders of magnitude with respect to reference DFT calculations, with little loss of accuracy in the regime relevant to charge transport in organics.
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.
authors.forename: Fruzsina
authors.initials: F
authors.lastname: Gajdos
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.
authors.forename: Siim
authors.initials: S
authors.lastname: Valner
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.|Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum , Universitätsstrasse 150, 44801 Bochum, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Hoffmann
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.
authors.forename: Jacob
authors.initials: J
authors.lastname: Spencer
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.
authors.forename: Marian
authors.initials: M
authors.lastname: Breuer
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.
authors.forename: Adam
authors.initials: A
authors.lastname: Kubas
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
authors.forename: Michel
authors.initials: M
authors.lastname: Dupuis
authors.affiliation: Department of Physics and Astronomy, University College London , London WC1E 6BT, U.K.
authors.forename: Jochen
authors.initials: J
authors.lastname: Blumberger