Excited polarons in poly(phenylene vinylene) and poly(diacetylene)

Abstract

We have employed the Su-Schrieffer-Heeger Hamiltonian to calculate the depths ${\mathrm{\omega }}_0$/${\mathrm{\Delta }}_0$ of the intragap states and binding energies ${\mathrm{\varepsilon }}_{\mathit{B}}$ of a variety of nonlinear excitations in poly(phenylene vinylene) and poly(diacetylene). These include the electronically excited polaron and polarexciton in which an electron has been promoted from a lower to an upper intragap level. The results for ${\mathrm{\varepsilon }}_{\mathit{B}}$ indicate a series of defect-pair annihilation processes that may be relevant to nonradiative decay of the polarexciton. The results for ${\mathrm{\omega }}_0$/${\mathrm{\Delta }}_0$ show that the dependence of ${\mathrm{\omega }}_0$/${\mathrm{\Delta }}_0$ on the soliton-confinement parameter γ for the bipolaron is quantitatively different from that given by the Brazovskii-Kirova relation.