Classical Dynamics Model

Abstract

In contrast to the binary collision model, the Classical Dynamics (CD) model studies the movement of atoms in a solid as a function of time. The term CD is here preferred in contrast to the most often applied term Molecular Dynamics (MD), because the problems addressed in this book deal nearly exclusively with atoms not molecules. The CD model takes the interaction with all neighbouring atoms into account. It can therefore be called a Multiple Interaction (MI) logic [3.1]. All moving atoms are followed in small time steps so that collisions between moving atoms are automatically included. A good overview of the CD model is given by Abraham [3.2], the basic physics is discussed by Hoover [3.3], and much practical advice is given in Beeler’s book [3.4] as well as in the more recent book by Allen and Tildesley [3.5]. Constraints such as constant stress [3.6], constant pressure [3.7] and constant temperature [3.8] lead to additional terms in the equations of motion and therefore ensembles other than the microcanonical. Even more choices are possible [3.9] but they are mainly used in the simulation of liquids, phase transformations and the like.