title: Clar's theory, pi-electron distribution, and geometry of graphene nanoribbons.
abstract: We show that Clar's theory of the aromatic sextet is a simple and powerful tool to predict the stability, the pi-electron distribution, the geometry, and the electronic/magnetic structure of graphene nanoribbons with different hydrogen edge terminations. We use density functional theory to obtain the equilibrium atomic positions, simulated scanning tunneling microscopy (STM) images, edge energies, band gaps, and edge-induced strains of graphene ribbons that we analyze in terms of Clar formulas. On the basis of their Clar representation, we propose a classification scheme for graphene ribbons that groups configurations with similar bond length alternations, STM patterns, and Raman spectra. Our simulations show how STM images and Raman spectra can be used to identify the type of edge termination.
authors.affiliation: IMPMC, Université Paris 6 et 7, CNRS, IPGP, 140 rue de Lourmel, 75015 Paris, France.
authors.forename: Tobias
authors.initials: T
authors.lastname: Wassmann
authors.forename: Ari P
authors.initials: AP
authors.lastname: Seitsonen
authors.forename: A Marco
authors.initials: AM
authors.lastname: Saitta
authors.forename: Michele
authors.initials: M
authors.lastname: Lazzeri
authors.forename: Francesco
authors.initials: F
authors.lastname: Mauri