Theoretical treatment of the dielectric response of all-trans-polyacetylene

First-principles electronic-band-structure results for polyacetylene are used to calculate the dielectric function ε(q,ω) of this material as a function of frequency ω and wave vector q. We find that our theoretical results when compared with the recent experimental results reported by Ritsko describe well many of the dominant features of the electron energy-loss spectra within a self-consistent interband transition linear response model for noninteracting parallel chains. A discussion is provided of other physical effects outside this simple model which may have a measurable effect on the optical and energy-loss spectra of polyacetylene.