Definition of the angle defining the molecular orientation along with a distribution at one interface. (a) ϕis the angle between the normal of the molecule plane and the normal of the interface plane (z-axis), i. e. the angle between the molecule plane and the interface plane. (b) Distribution of the angle ϕ(blue area) for the relaxed pentacene molecules at the interface of (-221)//(100) (pictogram in the left upper corner). Contributing pentacene molecules have a PTCDA neighbor with maximal atom-atom distance of 0.4 nm. The red dashed lines at 145.5 degree and 157 degree mark the values for the ideal morphology.
Poschlad et al. Nanoscale Research Letters 2012 7:248 doi:10.1186/1556-276X-7-248