  A dynamical model of the dielectric screening of conjugated polymers is
introduced and solved using the density matrix renormalization group method.
The model consists of a line of quantized dipoles interacting with a polymer
chain. The polymer is modelled by the Pariser-Parr-Pople (P-P-P) model. It is
found that: (1) Compared to isolated, unscreened single chains, the screened
1Bu- exciton binding energy is typically reduced by ca. 1 eV to just over 1 eV;
(2) Covalent (magnon and bi-magnon) states are very weakly screened compared to
ionic (exciton) states; (3) Screening of the 1Bu- exciton is closer to the
dispersion than solvation limit.
