Angle resolved photoemission spectra from the Si(001) surface have been calculated within the highly accurate one-step model. These spin integrated constant final state spectra for the valence bands have been investigated as a function of the emission direction of electrons. Especially, differences between right and left circularly polarized light in the spectra have been considered. A strong circular dichroism is found depending on the orbital composition of the contributing initial states. From various photoelectron patterns over the full 2π hemisphere an example for a p orbital dominated binding energy is presented and discussed.