title: Hole-vibronic coupling in oligothiophenes: impact of backbone torsional flexibility on relaxation energies.
abstract: Density functional theory calculations together with highly resolved gas-phase ultraviolet photoelectron spectroscopy have been applied to oligothiophene chains with up to eight thiophene rings. One of the important parameters governing the charge transport properties in the condensed phase is the amount of energy relaxation upon ionization. Here, we investigate the impact on this parameter of the backbone flexibility present in oligothiophenes as a result of inter-ring torsional motions. With respect to oligoacenes that are characterized by a coplanar and rigid backbone, the torsional flexibility in oligothiophenes adds to the relaxation energy and leads to the broadening of the first ionization peak, making its analysis more complex.
authors.affiliation: School of Chemistry and Biochemistry, Centre for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
authors.forename: Demetrio A da Silva
authors.initials: DA
authors.lastname: Filho
authors.forename: Veaceslav
authors.initials: V
authors.lastname: Coropceanu
authors.forename: Denis
authors.initials: D
authors.lastname: Fichou
authors.forename: Nadine E
authors.initials: NE
authors.lastname: Gruhn
authors.forename: Tonja G
authors.initials: TG
authors.lastname: Bill
authors.forename: Johannes
authors.initials: J
authors.lastname: Gierschner
authors.forename: Jérôme
authors.initials: J
authors.lastname: Cornil
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Brédas