In computational nanoscale science, we deal with many body nanostructures of all types composed of N atoms or molecules. The value of N can range from several hundred to several billions. To handle the energetics of these structures computationally, the most efficient way is to express the total interaction energies in these systems in terms of interatomic potentials that are functions of the atomic coordinates. The reason is that, even with the high-performing computing platforms and sophisticated simulation techniques available today, the existing quantum mechanical-based, or ab initio, strategies can handle nanoscale systems composed of, at most, a few hundred atoms. Interatomic potential energy functions will, therefore, be indispensable in modeling and simulation studies for a long time to come. © 2016, Springer International Publishing Switzerland.