title: Electronic structure of xDNA.
abstract: xDNA is an artificial duplex made of natural and benzo-homologated bases. The latter can be seen as a fusion between benzene and a natural base. We have used two different ab initio techniques, one based on B3LYP and a Gaussian expansion of the wave functions, and the other on GGA and plane-waves, to investigate the electronic properties of an xDNA duplex and a natural one with an analogous sequence. The calculations were performed in dry conditions, i.e., H atoms were used to neutralize the charge. It is found that the HOMO-LUMO gap of xDNA is about 0.5 eV smaller than that of B-DNA, independent of the technique used. The pi-pi* gap of xDNA is 1.3 or 1.0 eV smaller than that of B-DNA, depending on whether one uses B3LYP/6-31G or GGA/plane-waves, respectively. An analysis of how saturation changes the electronic properties of the nucleotide pairs that make up these duplexes suggests that different saturation schemes significantly affect the HOMO-LUMO gap value of xDNA and B-DNA. The same is not true for the pi-pi* gap. That xDNA has a smaller pi-pi* gap than B-DNA suggests that xDNA could be a plausible candidate for molecular-wire applications.
authors.affiliation: Center for Nanophase Materials Sciences and Computer Science and Mathematics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6494, USA. fuentescabma@ornl.gov
authors.forename: Miguel
authors.initials: M
authors.lastname: Fuentes-Cabrera
authors.forename: Xiongce
authors.initials: X
authors.lastname: Zhao
authors.forename: P R C
authors.initials: PR
authors.lastname: Kent
authors.forename: Bobby G
authors.initials: BG
authors.lastname: Sumpter
mesh_terms: D000465:Algorithms; D004247:DNA / Q000737:chemistry*; D004583:Electrons; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D013816:Thermodynamics
chemical_list: D004247:DNA