  Thin films formed from small molecules rapidly gain importance in different
technological fields. To explain their growth, methods developed for
zero--dimensional atoms as the film forming particles are applied. However, in
organic thin film growth the dimensionality of the building blocks comes into
play. Using the special case of the model molecule para--Sexiphenyl, we will
emphasize the challenges that arise from the anisotropic and one--dimensional
nature of building blocks. Differences or common features with other rodlike
molecules will be discussed. The typical morphologies encountered for this
group of molecules and the relevant growth modes will be investigated. Special
attention is given to the transition between flat lying and upright orientation
of the building blocks during nucleation. We will further discuss methods to
control the molecular orientation and describe the involved diffusion processes
qualitatively and quantitatively.
