  Transport properties, spectral function and optical conductivity of the
adiabatic one-dimensional Su-Schrieffer-Heeger (SSH) model are studied with
particular emphasis on the model parameters suitable for Rubrene single
crystals based field effect transistors. We show that the mobility, calculated
by using the Kubo formula for conductivity, vanishes unless we introduce an "ad
hoc" broadening of the system energy levels. Furthermore, the apparent
contradiction between angle resolved photoemission data and transport
properties is clarified by studying the behavior of the spectral function.
Finally, a peak in the optical conductivity at very low energy is obtained and
discussed in connection with the available experimental data for Rubrene based
devices.
