Theory and numerical study of excition dynamics in a disordered linear chain

摘要

We have fonnulated the exciton dynamics in a disordered linear chain with exciton wave functions given by the one-dimensional Frenkel exciton Hamiltonian with disorder. It is assumed that exciton-phononcoupling is weak and that the dynamics is governed by the competing processes of phonon scattering and radiative de<:;ay. The phonon scattering rate is given on the assumption that excitons do not change the site by the scattering. The strength of exciton-phonon coupling and the density 9f phonon states are irtdependent of energy. The radiative decay rate is given by the Einstein's A coefficient. The detail of the numerical procedure is also described. Absorption spectra, luminescence spectra, the time response of luminescence intensity, and temperature dependence are calculated for the model system of poly(di-n-hexylsilane) film. It is discussed that long-range dipole-dipole interaction is responsible for the luminescence depolarization.