The electronic structure of conjugated polymers

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