Theoretical characterization of the electronic properties of extended   thienylenevinylene oligomers
  We present semiempirical tight binding calculations on thienylenevinylene oligomers up to the hexadecamer stage (n=16) and ab initio calculations based on the local density approximation up to n=8. The results correctly describe the experimental variations of the gap versus size, the optical spectra, and the electrochemical redox potentials. We propose a simple model to deduce from the band structure of the polymer chain the electronic states of the oligomers close to the gap. We analyze the evolution of the gap as a function of the torsion angle between consecutive cells: the modifications are found to be small up to a ~30^{\circ}; angle. We show that these oligomers possess extensive pi-electron delocalization along the molecular backbone which makes them interesting for future electronic applications such as molecular wires. 
Christophe Krzeminski (IEMN), Christophe Delerue (IEMN), Guy Allan   (IEMN), Vincent Haguet (IEMN), Didier Sti\'evenard (IEM...
physics.chem-ph physics.comp-ph