Exact definition of optical phenomena and characteristics of ultrathin crystalline molecular films.

A complete and fully developed theory of all optical phenomena (refraction, reflection, absorption, and transparency) and the corresponding optical properties of ultrathin crystalline films (optical indices) are presented in this paper, especially along the direction in which the structure is spatially limited (perpendicular to surfaces). While these indices depend on the position of the crystallographic plane (where the mentioned optical phenomena occur) with respect to the two interfaces, these values can be measured/ determined in experiments only for the film as a whole. For these reasons, it is important to answer the question of how to define these optical indices precisely. [ABSTRACT FROM AUTHOR]