title: Electronic structure and aromaticity of graphene nanoribbons.
abstract: We analyse the electronic structure and aromaticity of graphene nanoribbons and carbon nanotubes through a series of delocalisation and geometry analysis methods. In particular, the six-centre index (SCI) is found to be in good agreement with the mean bond length (MBL) and ring bond dispersion (RBD) geometry descriptors. Based on DFT periodic calculations, three distinct classes of aromaticity patterns have been found for armchair graphene nanoribbons, appearing periodically as the width of the ribbon is increased. The periodicity in the band gap is found to be related to these aromaticity patterns. Also, the appearance of such distinct aromaticity distribution is explained within the framework of the Clar's sextet theory. Both delocalisation and geometry analysis methods are shown to be very fast and reliable tools for easily analysing the aromaticity in carbon nanosystems.
authors.affiliation: Research Group of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Member of the QCMM Alliance Ghent-Brussels, Pleinlaan 2 1050 Brussels, Belgium. fmartinm@vub.ac.be
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Martín-Martínez
authors.forename: Stijn
authors.initials: S
authors.lastname: Fias
authors.forename: Gregory
authors.initials: G
authors.lastname: Van Lier
authors.forename: Frank
authors.initials: F
authors.lastname: De Proft
authors.forename: Paul
authors.initials: P
authors.lastname: Geerlings