title: Electronic excitation and structural relaxation of the adenine dinucleotide in gas phase and solution.
abstract: The excited states and potential surfaces of the adenine dinucleotide are analyzed in gas phase and in solution using a correlated ab initio methodology in a QM/MM framework. In agreement with previous studies, a rather flat S1 surface with a number of minima of different character is found. Specifically, our results suggest that exciplexes with remarkably short intermolecular separation down to ~2.0 Å are formed. A detailed analysis shows that due to strong orbital interactions their character differs significantly from any states present in the Franck-Condon region. The lowest S1 energy minimum is a ππ* exciplex with only a small amount of charge transfer. It possesses appreciable oscillator strength with a polarization almost perpendicular to the planes of the two adenine molecules.
authors.affiliation: Institute for Theoretical Chemistry, University of Vienna, Währingerstr. 17, 1090 Vienna, Austria. felix.plasser@univie.ac.at
authors.forename: Felix
authors.initials: F
authors.lastname: Plasser
authors.forename: Hans
authors.initials: H
authors.lastname: Lischka
mesh_terms: D000227:Adenine Nucleotides / Q000737:chemistry*; D004583:Electrons; D005740:Gases / Q000737:chemistry; D008958:Models, Molecular; D010777:Photochemistry; D011789:Quantum Theory; D012996:Solutions / Q000737:chemistry
chemical_list: D000227:Adenine Nucleotides; D005740:Gases; D012996:Solutions