title: Electronic structure calculations on helical conducting polymers.
abstract: We present a study of the electronic structure and derived properties of polyfurane (PFu), polypyrrol (PPy), and polythiophene (PTh). Two spatial arrangements are considered: trans chain (tc-PFu, tc-PPy, tc-PTh) and cis α-helical (α-PFu, α-PPy, α-PTh). Even at the small sizes considered here, helical conformations appear to be stable. Band gaps of pure, undoped oligomers fall into the semiconductor range. Density of states (DOS) analysis suggest dense valence and conduction bands. Bond length alternation analysis predicts almost complete delocalization of the π clouds in all spatial arrangements. Doping with electron donors or electron-withdrawing impurities reduces all band gaps close to the metallic regime in addition to increasing the DOS for the valence and conduction bands.
authors.affiliation: Grupo de Química-Física Teórica, Instituto de Química, Universidad de Antioquia, AA 1226 Medellín, Colombia.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Ripoll
authors.forename: Andrei
authors.initials: A
authors.lastname: Serna
authors.forename: Doris
authors.initials: D
authors.lastname: Guerra
authors.forename: Albeiro
authors.initials: A
authors.lastname: Restrepo
mesh_terms: D003198:Computer Simulation; D004553:Electric Conductivity; D004583:Electrons; D005663:Furans / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D005663:Furans; D011108:Polymers; D011758:Pyrroles; D013876:Thiophenes