Dynamics of Frenkel excitons in pentacene

TL;DR

This paper investigates the dispersion relation of noninteracting Frenkel excitons in pentacene, fitting theoretical models to experimental data and analyzing the significance of perturbative corrections.

Contribution

It provides a detailed theoretical analysis of exciton dispersion in pentacene, determining exchange integrals from experimental data and showing perturbative corrections are negligible.

Findings

Theoretical dispersion curves match experimental data along four directions.

Perturbative corrections are negligible due to a large exciton gap.

Exchange integrals are determined through nonlinear fits to experimental data.

Abstract

The dispersion relation for noninteracting excitons and the influence of perturbative correction is examined in the case of pentacene structure. The values of exchange integrals are determined by the nonlinear fits to the experimental dispersion data obtained by inelastic electron scattering in Phys. Rev. Lett. \textbf{98}, 037402 (2007). We obtain theoretical dispersion curves along four different directions in the Brillouin zone which possess the same periodicity as the experimental data. We also showed that perturbative corrections are negligible since the exciton gap in dispersion relation is huge in comparison to exchange integrals.