  The perylene-3,4,9,10-tetracarboxylic-dianhydride (PTCDA) and
1,4,5,8-naphthalene-tetracaboxylic-dianhydride (NTCDA) are planar pi-stacking
organic molecules that have been shown to be excellent model compounds for
studying the growth and optoelectronic properties of organic semiconductor thin
films, particularly organic diodes. Some observations have shown that this
molecules, particularly PTCDA a brick-like shaped molecule easily forms
well-ordered films on various substrates due to its unique crystal structure
which is characterized by flat lying molecules In this work we will explore
some energetic and optical characteristics such as heats of formation, optic
GAP energies, electronic transitions and others of novel tow layer systems of
alternate layers of PTCDA and NTCDA by means of the semiempirical methods
Parametric Model 3 (PM3) and Zerner's Intermediate Neglect of Differential
Overlap (ZINDO/S) in Configuration Interaction mode.
