The electronic structure of conjugated polymers

The density matrix renormalisation group (DMRG) method is a powerful comput ational technique for calculating the electronic and geometrical structures of one-dimensional conjugated polymers. First, we solve the Pariser-Pan-Po ple-Peierls model for trans-polyene oligomers. We investigate the energies and solitonic structures. Next, we solve the Pariser-Parr-Pople model for t he light emitting phenyl polymers, and ascertain the nature of the excited states. Finally, we discuss how the DMRG method can be extended to ZINDO an d ah initio Hamiltonians, and to electron-phonon problems.