Density-functional studies of electronic properties of some conjugated polymers

We review a density-functional method for calculating the electronic properties of infinite, periodic, helical, isolated polymer chains. It is based on expanding the eigenfunctions to the Kohn-Sham equations in a basis of LMTOs, but is a full-potential method. As examples of applications we study C--C bond lengths for linear carbon chains and trans polyacetylene, and C--N bond lengths for polycarbonitrile. Furthermore, we study the dimerization as a function of charge, as well as the way the electronic properties of a conjugated polymer change in the presence of metal atoms and/or an applied DC field.