Doping effects on the electronic and structural properties of poly(para-phenylene) investigated from first-principles

We have performed density functional calculations for an ordered structure of Na doped poly(para-phenylene) (PPP) at a doping level of 1/3 Na atoms per phenyl ring. Relaxing the geometry results in a quinoid structure. The electronic band structure reveals a semiconductor to metal transition upon doping. The computed dielectric function (DF) including interband as well as free carrier contributions compares well with electron energy loss spectra on Na-doped para-hexaphenyl.