title: Benchmarking Time-Dependent Density Functional Theory for Excited State Geometries of Organic Molecules in Gas-Phase and in Solution.
abstract: We analyze potentials and limits of the Time-Dependent Density Functional Theory (TD-DFT) approach for the determination of excited-state geometries of organic molecules in gas-phase and in solution. Three very popular DFT exchange-correlation functionals, two hybrids (B3LYP and PBE0) and one long-range corrected (CAM-B3LYP), are here investigated, and the results are compared to the correlated RI-CC2 wave function approach. Solvent effects are further analyzed by means of a polarizable continuum model. A total of 15 organic chromophores (including both small molecules and larger push-pull systems) are considered as prototypes of n → π* and π → π* singlet excitations. Our analysis allows to point out specific correlations between the accuracy of the various functionals and the type of excitation and/or the type of chemical bonds involved. We find that while the best ground-state geometries are obtained with PBE0 and B3LYP, CAM-B3LYP yields the most accurate description of electronic and geometrical characteristics of excited states, both in gas-phase and in solution.
authors.affiliation: Laboratoire Structures, Propriétés et Modélisation des Solides (SPMS), CNRS UMR 8580, École Centrale Paris , Grande Voie des Vignes, F-92295 Châtenay-Malabry, France.
authors.forename: Ciro A
authors.initials: CA
authors.lastname: Guido
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark.
authors.forename: Stefan
authors.initials: S
authors.lastname: Knecht
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Kongsted
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, Università di Pisa , via Risorgimento 35, I-56126 Pisa, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Mennucci