Fundamentals of mesoscopic methods

After demonstrating the need for mesoscopic methods, this paragraph focuses on the physical concepts underlying these approaches. The three methods presented here (cf. § 2.5) derive from three different treatments of inhomogeneous systems. The first two are based on the principle of molecular dynamics. The first is a means of increasing the integration step length in order to gain access to longer simulation times. In the second approach, derived from molecular dynamics, particles containing several atoms are subjected to additional forces, introducing dissipative effects not present in so-called classical molecular dynamics. The third approach takes a continuous view of the mesoscopic scale, using density functional methods. Given that this method is quite different from the other approaches, a greater depth of the theoretical notions necessary for its understanding will be presented. These...