title: The Importance of Short- and Long-Range Exchange on Various Excited State Properties of DNA Monomers, Stacked Complexes, and Watson-Crick Pairs.
abstract: We present a detailed analysis of several time-dependent DFT (TD-DFT) methods, including conventional hybrid functionals and two types of nonempirically tuned range-separated functionals, for predicting a diverse set of electronic excitations in DNA nucleobase monomers and dimers. This large and extensive set of excitations comprises a total of 50 different transitions (for each tested DFT functional) that includes several n → π and π → π* valence excitations, long-range charge-transfer excitations, and extended Rydberg transitions (complete with benchmark calculations from high-level EOM-CCSD(T) methods). The presence of localized valence excitations as well as extreme long-range charge-transfer excitations in these systems poses a serious challenge for TD-DFT methods that allows us to assess the importance of both short- and long-range exchange contributions for simultaneously predicting all of these various transitions. In particular, we find that functionals that do not have both short- and full long-range exchange components are unable to predict the different types of nucleobase excitations with the same accuracy. Most importantly, the current study highlights the importance of both short-range exchange and a nonempirically tuned contribution of long-range exchange for accurately predicting the diverse excitations in these challenging nucleobase systems.
authors.affiliation: Department of Chemical & Environmental Engineering and Materials Science & Engineering Program, University of California, Riverside , Riverside, California 92521, United States.
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Raeber
authors.affiliation: Department of Chemical & Environmental Engineering and Materials Science & Engineering Program, University of California, Riverside , Riverside, California 92521, United States.
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Wong
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004583:Electrons; D009690:Nucleic Acid Conformation; D011789:Quantum Theory
chemical_list: D004247:DNA