Exciton dynamics in molecular crystals from line shape analysis. The use of spectral moments and correlation functions

A method for elucidating exciton dynamics from the profile of ωε{lunate}i(ω) is developed and illustrated by using anthracene crystal reflectance data. From the Green's function for the exciton-phonon system, terms contributing to each spectral moment are rendered explicit. The Green's function is related to certain correlation functions which together with the spectral moments are evaluated from the spectral data