Just a few years ago, materials research had mainly to do with macroscopic systems. The situation changed fundamentally with the rise of nanotechnology. Now properties which could have been well defined and clearly fixed for macroscopic (bulk) systems no longer can be assigned to nanostructures at least not in the same simple way.

In this section, we would like to discuss this problematic nature connected to the characterization of nanosystems. First, the difficulties are outlined at the example of the thermal stability of nanostructures, then we go further into detail considering other basic material properties. In this context, it will become apparent that the standard model of solid-state physics fails at the nanometer level, that is, characterization of nanostructures has to be performed by other means. The alternatives, arising from the analysis of MD calculations, are compiled in the final section, and wherever possible, we illustrate the topics with exemplary MD studies.