Modeling and simulation tools are an integral part of the design process utilized by the systems engineer and are also useful to the nanotechnologist for gaining understanding of nanoscale phenomena. However, modeling and simulation in these two contexts can differ greatly in form and function. This chapter will serve to explain how modeling and simulation are used by the systems engineer and conversely by the nanotechnologist. Figure 10.1 presents a framework for the entire chapter. Overviews of theories used for modeling at the nanoscale will

be given, and challenges faced in trying to capture the important nanoscale phenomena will be reviewed. As nanoscale components merge into the systems engineering framework, up to 10 orders of magnitude are spanned. To predict system performance, material properties and component behavior must be translated from computations at the atomistic scale to the nanoscale and then up to the micro-and macroscales without losing important effects or propagating error by oversimplifying behaviors or making excessive assumptions. This chapter will explore how nanoscale theory, modeling, and simulations fit into the traditional systems engineering framework and what obstacles need to be overcome to enable the systems engineer’s traditional approach to design.