Abstract
Interatomic bond is of quantum mechanical origin and has many-atom characters. Thereby it is generally difficult to express the interatomic potential empirically in terms of simple analytic functions. Applicability of such a simple form is certainly limited and a success in one case does not necessarily guarantee success in other cases. Recent progress in the first-principles electronic structure calculation enables us to evaluate the forces acting on atoms in any circumstance equally well. In this connection, a brief review of the CarParrinello method will be given and an example of its application to silica will be presented.
