Valence effective Hamiltonian technique for nitrogen containing polymers: Electronic structure of polypyrrole, pyrolized polyacrylonitrile, paracyanogen, polymethineimine, and derivatives

We present the parametrization of nitrogen for use in the valence effective Hamiltonian (VEH) technique. We describe five different parametrization schemes and discuss the quality of the results each of them affords. The VEH method is then applied to the study of the electronic structure of nitrogen containing polymers of interest with regard to the conducting polymers area. These polymers include polypyrrole, poly-β-dimethylpyrrole, poly-N-methylpyrrole, pyrolized polyacrylonitrile, paracyanogen (polypyrazinopyrazine), and polymethineimine [CH=N]_x. Parameters related to the conductivity properties upon doping such as ionization potentials, bandgaps, and bandwidths, are discussed in detail.