  Spectral and transport properties of small molecule single-crystal organic
semiconductors have been theoretically analyzed focusing on oligoacenes, in
particular on the series from naphthalene to rubrene and pentacene aiming to
show that the inclusion of different electron-phonon couplings is of paramount
importance to interpret accurately the properties of prototype organic
semiconductors. While, in the case of rubrene, the coupling between charge
carriers and low frequency inter-molecular modes is sufficient for a
satisfactory description of spectral and transport properties, the inclusion of
electron coupling to both low frequency inter-molecular and high frequency
intra-molecular vibrational modes is needed to account for the temperature
dependence of transport properties in smaller oligoacenes.
